DEV Community: brandon_wallace

Make Your Tmux Status Line 100% Better With Bash

brandon_wallace — Mon, 12 Dec 2022 03:35:28 +0000

Did you know that you can easily use Bash to display information on the Tmux status line? Because of that the possibilities of what you can do are almost endless. You can display all sorts of useful information such as:

Hostname
IP address
Netmask
Gateway
Memory
CPU temperature
System load
Battery meter
VPN status
Time
Date
Weather report
Git status

In this article I will show you an easy way to add information to your Tmux status line.

Requirements

lm-sensors

Here is the default status line.

Here is the status line enhanced to show more information.



# Debian/Ubuntu based distributions
$ sudo apt install tmux


# Redhat/Fedora based distributions
$ sudo dnf install tmux

Check your Tmux version. Currently I am using version 3.3a.



$ tmux -V

# Output
tmux 3.3a

If you do not have a .tmux.conf create one in your home directory.



$ touch .tmux.conf

I will start out with a basic .tmux.conf configuration. Edit .tmux.conf and add the following lines.




# .tmux.conf

bind r source-file ~/.tmux.conf \; display-message "RELOADING CONFIGURATION FILE…"

# STATUS LINE
set -g status on
set -g status-interval 1
set -g status-justify centre # Careful! It is spelled "centre" not "center".
set -g status-style fg=white,bg=black

# Highlight the current window.
setw -g window-status-current-style fg=white,bg=red,bright

# LEFT STATUS
set -g status-left-length 100
set -g status-left-style default
set -g status-left " "

# RIGHT STATUS
set -g status-right-length 100
set -g status-right-style default
set -g status-right " "

Status Line Left Side

Tmux has same built in variables that you can use to display information such as #h to display the hostname. View the man page for more information.




$ man tmux

Add #h in between the double quotes




set -g status-left "#h"

You need to reload Tmux to see the changes. To reload Tmux you can type exit then launch Tmux again or you can reload Tmux by press the CTRL+b then r.
After reloading Tmux you will see the hostname of your computer on the status line.

Adding the IP address and netmask to Status Line

All we need to do to customize the status line is to add Bash one-liners. To add Bash commands to the command line you only need to place each command inside a hash mark and parenthesis #( <my-command> ).

I use this Bash command to get the IP address of the enp4s0 Ethernet interface.




$ ip addr | grep -e 'state UP' -A 2 | awk '/inet /{printf $2}'

# Output

192.168.0.101/26

I can add the command to the Tmux status line by placing it in between the parenthesis like this.




set -g status-left "#h #(ip addr | grep -e 'state UP' -A 2 | awk '/inet /{printf $2}')"

Adding the CPU Temperature to Status Line

Next I want to add the CPU temperature. To make that work you must use lm-sensors. Install lm-sensors.




# Debian/Ubuntu based distributions
$ sudo apt install lm-sensors


# Redhat/Fedora based distributions
$ sudo dnf install lm_sensors

Enable lm-sensors with this command and follow the prompts.



$ sudo sensors-detect

Run the sensors command to see the output. From the output you will need to figure out which line displays information about the CPU. The line you need might be labeled Tccd1 or CPU. Add the -f argument to the sensors command to see the temperature in Fahrenheit.




$ sensors -f

# Partial Output 

intel-isa-0000
Adapter: ISA adapter
fan1:           0 RPM
CPU:          +96.8°F  
GPU:              N/A  
temp3:        +96.8°F  
temp4:        +32.0°F  
temp5:        +96.8°F  
temp6:        +96.8°F  
temp7:        +96.8°F  
temp8:            N/A  

intel-pci-0400
Adapter: PCI adapter
vddgfx:      794.00 mV 
vddnb:       604.00 mV 
edge:         +95.0°F  
PPT:           3.16 W  

BAT0-acpi-0
Adapter: ACPI interface
in0:          17.27 V  
[....]

Add this code #(sensors -f | awk '/CPU/{printf $2}') to the end of the left status line. This command uses awk to find the row with the text CPU and print the second column.




set -g status-left "#h #(ip addr show enp4s0 | awk '/inet /{printf $2}') #(sensors -f | awk '/CPU/{printf $2}')"

Adding Memory to the Status Line

Next, I want to view the amount of memory used, the total memory, and calculate the percentage of memory in use. To do that I use the free command.




# Amount of memory used / total amount of memory
$ free -m -h | awk '/Mem/{printf $3"/"$2}'

# Output

3.3Gi/62Gi

# Calculate percentage of memory used

$ free -m | awk '/Mem/{printf "%.2f%", 100*$3/$2}'

# Output

2.1%

Careful here! To get the memory command to display properly in the Tmux status line requires that certain characters be escaped.
Here I am using the backward slash \ to escape the double quote \", the period \., the percent sign \%, and the forward slash \/.

Before escaping characters:




#(free -m -h | awk '/Mem/{printf $3"/"$2}') #(free -m | awk '/Mem{printf "%.2f%", 100*$2/$3}')"

After escaping characters:




#(free -m -h | awk '/Mem/{printf $3\"\/\"$2}') #(free -m | awk '/Mem{printf \"\%\.2f\%\", 100*$2/$3}')"

The status left should now look like this.




set -g status-left "#h #(ip addr | grep -e 'state UP' -A 2 | awk '/inet /{printf $2}') #(sensors | awk '/CPU/{printf $2}') #(free -m -h | awk '/Mem/{printf $3\"\/\"$2}') #(free -m | awk '/Mem{printf \"\%\.2f\%\", 100*$2/$3}')"

Adding the Battery Level to Status Line

I want to see the battery level and see if it is charging on not. To do that I can check the /sys file system for the battery information.

If your terminal supports unicode characters you can add an unicode characters to the status bar.

I will test to see if the power cable is plugged in and show a lighting bolt icon if it is. I will show the percentage of battery remaining next to the lightning bolt.

If $(cat /sys/class/power_supply/AC/online) is equal to 1 the lightning bolt will display.

Add these lines to the end of the left status line.




#([ $(cat /sys/class/power_supply/AC/online) == 1 ] && printf %s'🗲') 

#( $(cat /sys/class/power_supply/BAT0/capacity)\% )

The left status line should look something like this.




set -g status-left "#h #(ip addr | grep -e 'state UP' -A 2 | awk '/inet /{printf $2}') #(sensors | awk '/CPU/{printf $2}') #(free -m -h | awk '/Mem/{printf \$3\"\/\"\$2\}') #(free -m | awk '/Mem{printf 100*$2/$3" %"}') #([ $(cat /sys/class/power_supply/AC/online) == 1 ] && printf %s'🗲') #(cat /sys/class/power_supply/BAT0/capacity)\%"

Adding the VPN to Status Line

I want to check if the VPN is up and see the IP address assigned to it. Depending on the VPN you use you might have to check the tun0 or ppp0 interface.




ip a | egrep 'ppp0|tun0' -A 2 | awk '/inet /{printf $2}'

# Output

10.20.3.45

Add this to the end of the left status line.




#([ ! -z $(ip a | egrep 'ppp0|tun0' -A 2 | awk '/inet /{printf $2}') ] && echo $(ip a | egrep 'ppp0|tun0' -A 2 | awk '/inet /{printf \"VPN \"$2}'))

My status line now looks like this.




set -g status-left "#h #(ip addr | grep -e 'state UP' -A 2 | awk '/inet /{printf $2}') #(sensors | awk '/CPU/{printf $2}') #(free -m -h | awk '/Mem/{printf \$3\"\/\"\$2\}') #(free -m | awk '/Mem{printf 100*$2/$3" %"}') #([ $(cat /sys/class/power_supply/AC/online) == 1 ] && printf %s'🗲') #(cat /sys/class/power_supply/BAT0/capacity)\% #([ ! -z $(ip a | egrep 'ppp0|tun0' -A 2 | awk '/inet /{printf $2}') ] && echo $(ip a | egrep 'ppp0|tun0' -A 2 | awk '/inet /{printf \"VPN \"$2}'))"

Status Bar Right Side

Now let’s configure the right side.

I will get the load average using the uptime command.




$ uptime

# Output

02:39:38 up 12:18,  1 user,  load average: 0.20, 0.11, 0.10

The number of columns in the output can change so depending on the time. To get around that problem I use $(NF) to get the last column and tr to remove the colon characters.

Add this to the right status line option with escaped characters in between the double quotes.




set -g status-right "#(uptime | awk '{printf \$(NF-2)\" \"\$(NF-1)\" \"\$(NF)}' | tr -d ',')"

The last thing I will add is the date, time, and timezone using variables to status-right. Tmux uses strftime formatting to display variables. Given that, I can view the date and time using a custom format. Example: %F represents YYYY-mm-dd %T represents HH:MM:SS . See the man page for more information man strftime.

Add that to the end of the right status line.




set -g status-right "#(uptime | awk '{printf \$(NF-2)\" \"\$(NF-1)\" \"\$(NF)}' | tr -d ',') %F %T %Z"

Adding a Bash Script

If you needed to configure more complicated code than what could fit on one line you can make a separate Bash file and add it like this.




set -g status-right "#( example.sh )"




$ cat example.sh

#!/bin/bash
# example.sh

# Get the IP address dynamically
function get_ip_address() {
    mapfile -t iface_arr < <(echo $(ls /sys/class/net/))
    for iface in $iface_arr; do 
        if [ "$(cat /sys/class/net/$iface/operstate)" == "up" ]; then
            printf "    %s\n" "${iface^^}: $(ip addr show $iface | awk '/inet /{printf $2}')"; 
        fi
    done
}

get_ip_address

Adding Color

Run this code in your terminal to see what colors you have available.




#!/bin/bash

for num in {0..255}; do  
    printf "%s\033[38;5;${num}mcolour${num}\033[0m \t"; 

    if [ $(expr $((num+1)) % 8) -eq 0 ]; then
        printf "\n"
    fi
done

Now you can add color to your status line. Add foreground colors by setting a #[fg=<colourN>] or #[bg=<colourN>] variable to the color of your choice.
fg= is for the foreground color bg= is to set the background color in between square brackets. Use #[default] to back to the default colors.




set -g status-left "#[fg=colour220] #h #[fg=colour47] #(ip addr | grep -e 'state UP' -A 2 | awk '/inet /{printf $2}') #[colour27] #(sensors -f | awk '/CPU/{printf $2}') #[default]"

The status lines can get quite long. If you do not like long lines use the backslash to break it up.



set -g status-left "#[fg=colour220]#h</span>

  
  
  [fg=colour196] #(ip addr | grep -e 'state UP' -A 2 | awk '/inet /{printf $2}')</span>



  
  
  [fg=colour39] #(sensors | awk '/CPU/{printf $2}')</span>



  
  
  [fg=colour40] #(free -m -h | awk '/Mem/{printf \$3\"\/\"\$2}')</span>



  
  
  [fg=colour128] #(free -m | awk '/Mem{printf 100*$2/$3" %"}')</span>



  
  
  [fg=colour202] #([ $(cat /sys/class/power_supply/AC/online) == 1 ] && printf %s'🗲') #(cat /sys/class/power_supply/BAT0/capacity)\%</span>



  
  
  [fg=colour7] #([ ! -z $(ip a | egrep 'ppp0|tun0' -A 2 | awk '/inet /{printf $2}') ] && echo $(ip a | egrep 'ppp0|tun0' -A 2 | awk '/inet /{printf \"VPN \"$2}'))</span>



  
  
  [default]"

Complete Status Line Configuration



# .tmux.conf

bind r source-file ~/.tmux.conf \; display-message "RELOADING CONFIGURATION FILE…"

# STATUS LINE

set -g status on

set -g status-interval 1

set -g status-justify centre # Careful! It is spelled "centre" not "center".

set -g status-style fg=white,bg=black

# Highlight the current window.

setw -g window-status-current-style fg=white,bg=red,bright

# LEFT STATUS

set -g status-left-length 100

set -g status-left-style default

set -g status-left "#[fg=colour220]#h</span>

  
  
  [fg=colour196] #(ip addr | grep -e 'state UP' -A 2 | awk '/inet /{printf $2}')</span>



  
  
  [fg=colour39] #(sensors | awk '/CPU/{printf $2}')</span>



  
  
  [fg=colour40] #(free -m -h | awk '/Mem/{printf \$3\"\/\"\$2}')</span>



  
  
  [fg=colour128] #(free -m | awk '/Mem{printf 100*$2/$3" %"}')</span>



  
  
  [fg=colour202] #([ $(cat /sys/class/power_supply/AC/online) == 1 ] && printf %s'🗲') #(cat /sys/class/power_supply/BAT0/capacity)\%</span>



  
  
  [fg=colour7] #([ ! -z $(ip a | egrep 'ppp0|tun0' -A 2 | awk '/inet /{printf $2}') ] && echo $(ip a | egrep 'ppp0|tun0' -A 2 | awk '/inet /{printf \"VPN \"$2}'))</span>



  
  
  [default]"


# RIGHT STATUS

set -g status-right-length 100

set -g status-right-style default

set -g status-right "#[fg=colour39] #(uptime | awk '{printf \$(NF-2)\" \"\$(NF-1)\" \"\$(NF)}' | tr -d ',')</span>

  
  
  [fg=colour40] %F</span>



  
  
  [fg=colour128] %T</span>



  
  
  [fg=colour202] %Z</span>



  
  
  [default]"

Conclusion

You can now easily have a Bash display useful information on the Tmux status line. I hope you learned something new and enjoyed reading this article.

Follow me on Dev.to and Github.

Feel free to leave comments, questions, and suggestions.

Easy Automatic Code Deployment With Git

brandon_wallace — Mon, 08 Nov 2021 17:09:13 +0000

Introduction

I will show you how to deploy code to a live server easily with Git.

Let's say you have already deployed your project to a live server. A few days later you receive valuable feedback on your project from another developer. You decide to make some improvements to the project. You work in your local Git repository to make the changes. You test everything to make sure it is working the way you intended it to work. Then you commit the changes in your code to your local Git repository. Then you push those changes to Github.

How do you go about getting those improvements to the live server? Would you log into the server and meticulously edit the file manually?

There is an easy way to deploy code to a live server - use Git. All you need it is the ability to SSH to the server.

Here is the syntax for the git push command:

$ git push <repository> <branch_name>

Example:

$ git push origin main

The origin is first repository that is set up and usually represents the repository connected to the Github website.

To get code to a live server, I will create a second repository on the live server to push code to. I will call the second repository "prod" to represent the repository on the live production server.

After pushing code to the "origin" repository I will be able to push to "prod" any code ready for production.

When I am ready to push code to the production server I run this command.

$ git push prod main

On the server

We need two directories on the server, one for the application which holds the production code, and one directory for the Git bare repository.

Directory for production code:

/var/www/my_project/

Git bare repository:

/var/repos/my_project.git/

Set up a repository on the server.

The first step to set this up is to create a bare repository on the web server where you will run the application.

SSH to your server. My server has the user brandon and the IP address 123.45.67.89. So I use this command.

$ ssh brandon@123.45.67.89

Create the directory as a Git bare repository with a .git at the end of the name.

$ sudo mkdir -p -v /var/repos/my_project.git/

Set the permissions on the directory.

$ sudo chown $USER:$USER /var/repos/my_project.git/

Move into the my_project.git/ directory.

cd /var/repos/my_project.git/

Run the git init --bare command inside the /var/repos/my_project.git/ directory.

$ git init --bare

The directory structure should look like this.

$ tree --dirsfirst -F
.
├── branches/
├── hooks/
│   ├── applypatch-msg.sample*
│   ├── commit-msg.sample*
│   ├── fsmonitor-watchman.sample*
│   ├── post-update.sample*
│   ├── pre-applypatch.sample*
│   ├── pre-commit.sample*
│   ├── pre-merge-commit.sample*
│   ├── prepare-commit-msg.sample*
│   ├── pre-push.sample*
│   ├── pre-rebase.sample*
│   ├── pre-receive.sample*
│   ├── push-to-checkout.sample*
│   └── update.sample*
├── info/
│   └── exclude
├── objects/
│   ├── info/
│   └── pack/
├── refs/
│   ├── heads/
│   └── tags/
├── config
├── description
└── HEAD

Creating a hook to perform an action.

A hook will allow you to run a script when a particular action occurs. There are hooks that run on the client and hooks that run on the server. I will set up the server-side hook post-receive that will run once a git push has finished executing.

Create a file called post-receive in the hooks directory.

$ touch hooks/post-receive

Use any text editor to edit the post-receive file.

$ vim hooks/post-receive

Add the following content, change the paths to reflect your set up.

#!/bin/sh

git --work-tree=/var/www/my_project/ --git-dir=/var/repos/my_project.git checkout -f main

The post-receive script is not executable.

$ ls -lF hooks/post-receive 

-rw------- 1 brandon brandon 0 Nov  2 21:19 hooks/post-receive

Make the script executable by running the chmod command.

$ chmod +x hooks/post-receive

$ ls -lF hooks/post-receive 

-rwx------ 1 brandon brandon 0 Nov  2 21:19 hooks/post-receive*

On my laptop

Connect your local repository to the server repository.

On the client machine where my local repository is located I will connect that repository to the one I created on the live server.

Create a local repository with the same name as the directory on the server minus the .git extension.

$ mkdir my_project/

Move into the directory.

$ cd my_project/

Set up git in the project directory with a few basic files.

$ git init

$ touch .gitignore readme.md LICENSE

Add content to the readme.md file.

$ echo '# My Auto Deploy Project' >> readme.md

With any text editor add a simple index.html file to the project.

$ vim index.html

Add the following content to the index.html file.

<!DOCTYPE html>
<html lang="en">

  <head>

    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width,initial-scale=1" />
    <meta name="description" content="My auto deploy project.">
    <link rel="stylesheet" href="style.css">
    <title>Hello World!</title>

  </head>

  <body>

    <h1>Hello World!</h1>

  </body>

</html>

Add all the files to Git and commit the changes.

$ git add --all

$ git commit -m "First commit"

Create a new repository on Github without the readme.md, .gitignore, or LICENSE. We have already created those files for the Github repository. Name the Github repository the same as the local repository. My local repository is called my_project so I use the same name to create the Github repository. See screenshot below.

Connect the local repository to Github. Make sure the branch is called main.

$ git remote add origin git@github.com:brandon-wallace/my_project.git

$ git branch -M main

Set origin as the default repository to push to.

$ git push -u origin main

Enumerating objects: 5, done.
Counting objects: 100% (5/5), done.
Delta compression using up to 4 threads
Compressing objects: 100% (3/3), done.
Writing objects: 100% (5/5), 550 bytes | 550.00 KiB/s, done.
Total 5 (delta 0), reused 0 (delta 0), pack-reused 0
To github.com:brandon-wallace/my_project.git
 * [new branch]      main -> main
Branch 'main' set up to track remote branch 'main' from 'origin'.

I have successfully connected the local repository to Github. Now I will connect the local repository to the live production server. My server has the IP address 123.45.67.89 and SSH on port 22 so I run this command with the full path to the my_project.git directory.

Syntax:

$ git remote add <remote_repository> ssh://<username>@<server_ip>:<port>/path/to/<project>.git

This is the command I run.

$ git remote add prod ssh://brandon@123.45.67.89:22/var/repos/my_project.git

When I want to push code to the production server. I run this command.

$ git push prod main

Enumerating objects: 5, done.
Counting objects: 100% (5/5), done.
Delta compression using up to 4 threads
Compressing objects: 100% (3/3), done.
Writing objects: 100% (5/5), 550 bytes | 550.00 KiB/s, done.
Total 5 (delta 0), reused 0 (delta 0), pack-reused 0
remote: Switched to branch 'main'
To 123.45.67.89:/var/www/my_project_repo/my_project.git
 * [new branch]      main -> main

View the remotes. This shows that there are two remote repositories available, prod and origin.

$ git remote -v

prod    ssh://brandon@123.45.67.89:22/var/repos/my_project.git (fetch)
prod    ssh://brandon@123.45.67.89:22/var/repos/my_project.git (push)
origin  https://github.com/brandon-wallace/my_project.git (fetch)
origin  https://github.com/brandon-wallace/my_project.git (push)

I will make some changes to the project and push those to the production server.

$ touch style.css

Add some content to the CSS file with any text editor.

$ vim sytle.css

# Example content

html {
    font-size: 100%;
}

body {
    background: #FFFFFF;
    font-family: sans-serif;
    font-weight: 400;
    line-height: 1.75;
    color: #000000;
}

h1 {
    margin-top: 0;
    font-size: 3.052rem;
}

Add the new CSS file. Commit the changes to the repository.

$ git add style.css

$ git commit -m "Add CSS file"

# Output

[main 8881680] Add CSS file
 1 files changed, 27 insertions(+), 3 deletions(-)
 create mode 100644 style.css

Right now, on the server I can see four files in my_project/.

$ /var/www/my_project/ $ ls -l
total 12
-rw-r--r-- 1 brandon brandon  319 Nov  7 10:25 index.html
-rw-r--r-- 1 brandon brandon    0 Nov  7 10:25 LICENSE
drwxr-xr-x 8 brandon brandon 4096 Nov  7 10:25 my_project.git
-rw-r--r-- 1 brandon brandon   25 Nov  7 10:25 readme.md

Push the changes to the production server.

$ git push prod main

Enumerating objects: 6, done.
Counting objects: 100% (6/6), done.
Delta compression using up to 4 threads
Compressing objects: 100% (4/4), done.
Writing objects: 100% (4/4), 623 bytes | 623.00 KiB/s, done.
Total 4 (delta 2), reused 0 (delta 0), pack-reused 0
remote: Already on 'main'
To 123.45.67.89:/var/repos/my_project.git
   083f700..8881680  main -> main

Now on the server I can see the style.css I just pushed to the prod repository running on the live server.

/var/www/my_project $ ls -l
total 16
-rw-r--r-- 1 brandon brandon  362 Nov  7 10:56 index.html
-rw-r--r-- 1 brandon brandon    0 Nov  7 10:25 LICENSE
drwxr-xr-x 8 brandon brandon 4096 Nov  7 10:56 my_project.git
-rw-r--r-- 1 brandon brandon   25 Nov  7 10:25 readme.md
-rw-r--r-- 1 brandon brandon  365 Nov  7 10:56 style.css

Troubleshooting

First, check carefully for spelling errors is highly recommended.

If you get -bash: git: command not found error install git.

$ sudo apt update

$ sudo apt install git

You get the error:

ssh: Could not resolve hostname github.com: Temporary failure in name resolution
fatal: Could not read from remote repository...

You need to set up SSH keys on Github.

Conclusion

I hope you learn something new by reading this article. Using Git you can easily push changes to a project to a live production server.

Feel free to leave feedback, comments, or suggestions.

How To Install Debian 11 Bullseye Expert Mode Minimal Install

brandon_wallace — Tue, 24 Aug 2021 15:10:43 +0000

Introduction

In this article, I will show you how to do a minimal installation of Debian 11 Bullseye in "Expert Install" mode.

The Debian installer is very flexible. You can easily use the installation media to install Debian as a server or a desktop/laptop. I will go over a minimal installation step by step and include an option to install a desktop environment of your choice. Doing an "Expert Install" will provide you with a few advanced options which allow for better customization of the operating system.

Why Debian?

These are some of the reasons why people install Debian.

Very stable and secure
Has wide hardware support
Is a community project of volunteers around the world
Has a flexible installer that allows for customization
Upgrades smoothly from one release to the next release

Here are the requirements for Debian 11 Bullseye.

Requirements	Minimum	Recommended
RAM:	512MB	2GB
Processor (CPU):	1GHz
Hard Drive:	10GB

A minimal installation is great for a server set up. The benefit of setting up a server with a command line interface you will not use a lot of resources.

Here is a server that contains 2 gigabytes of RAM. You see this server is using is only using 61 megabytes of RAM without a graphical user interface!



brandon@debian $ free -m
              total        used        free
Mem:           1982          61        1920
Swap:           975           0         975

After installing the full Xfce desktop the RAM usage increased to 311 megabytes.

You can use almost any computer for this. If you have some old hardware laying around such as a

Desktop
Laptop
A Mac computer
Used server hardware

What can you do with a Linux server? Here are some examples.

Private Git server
Web server
File server with NFS or Samba
Media server
Database server
DNS server
NTP server
Email server
Ad blocker
Set up RAID (Redundant Array of Independent Disks)
Explore the GNU/Linux operating system

Installation

Download the amd64 Debian 11 Bullseye firmware-11.5.0-amd64-netinst.iso file from the Debian.org website. Pick the architecture supported by your computer. For example, if your computer is really old it might not support 64-bit (amd64). In that case, you will need the 32-bit ISO (i386) file.

If you need non-free firmware to have drivers to set up for hardware such as WiFi use this ISO file to install Debian.

firmware-11.5.0-amd64-netinst.iso
(Recommended - includes non-free firmware)

debian-11.5.0-amd64-netinst.iso
(non-free firmware NOT included)

Install the ISO file to a USB flash drive using one of these tools.

Rufus
Etcher
Unetbootin
Pendrive Linux

If have Linux installed already you can run the dd command to install the ISO to the USB flash drive.
WARNING!! If you use dd make sure you write to the correct /dev/sdX drive.

I list my drives in the computer like this.



$ sudo fdisk -l 2> /dev/null | egrep 'Disk /dev/'

# Output

Disk /dev/sdb: 254.8 GiB
Disk /dev/sda: 120.9 GiB 
Disk /dev/sdc: 15.9 GiB  <== My USB flash drive

On my computer the flash drive is /dev/sdc so I run this command.



$ sudo dd if=firmware-11.5.0-amd64-netinst.iso of=/dev/sdc bs=4M status=progress; sync

# Or

$ sudo dd if=debian-11.5.0-amd64-netinst.iso of=/dev/sdc bs=4M status=progress; sync

Find out how to boot off of the USB flash drive. Every manufacture has a different key to press to get to the boot menu. On my computer I press the F12 key to select the boot menu.

Once you boot off of the USB flash drive the installation menu will come up.
Select "Advanced options".

Select "Expert Install".

Choose a language.

I am choosing English because that is one of the languages I speak.

Select your location to set the correct time zone.

The locale sets character encoding, date and time formatting, currency, default paper size, etc. The default setting should be fine. For US English the default is "en_US.UTF-8". No need to change this setting.

You have the option to add additional locales here if you need them. I will use the default "en_US.UTF-8" set on the previous page. Press "Continue".

Here you can select the keyboard layout of your preference such as Dvorak. I will stick with the default "American English" here.

Time to detect the installation media which is the USB flash drive that you booted off earlier.

Press "Continue".

Installer components get loaded from the USB installation media.

Optional specialized components can be selected here if you need them. By default nothing is selected. Press "Continue".

Network hardware will be detected here.

Configure the network connection.

Select "Yes" to set the IP address using DHCP (Dynamic Host Control Protocol). This is recommended for a desktop/laptop. If you select "Yes", skip the "For a static IP" section. The IP address will be configured via DHCP and you will move on to setting the hostname.

Select "No" to set a static IP address. A static IP address is recommended for a server.

For a static IP I set my IP address to 192.168.12.34 since I know that will work on my network.

For a static IP I set the netmask to /24 which is 255.255.255.0.

For a static IP I set the gateway to 192.168.12.1 because that is the gateway of my network.

For a static IP I set three public DNS (Domain name servers) using a space as a delimiter.

1.1.1.1 <== Cloudflare DNS
208.67.222.222 <== OpenDNS
8.8.8.8 <== Google DNS

For a static IP Verify the networking information is correct. Click "Yes" to accept the changes.

Wait 3 seconds for the network link to be detected. Press "Continue".

Set the hostname for the computer.

Set a domain name for the system. It is better to make something up here. For more information see RFC6762

Set up users and passwords for the system.

Enable shadow passwords. Select "Yes" here. This is for security. Shadow passwords will allow the hashed password to be stored in /etc/shadow, which is only readable by root.

For added security, select "No" for "Allow login as root". Users will be able to type sudo to run root commands.

Type your full name here. Applications that display your full name will use this.

Type the user name which you will use to log into the computer.

Set a strong password here.

Re-type the password you selected to make sure it is correct.

Set the system clock.

If you wish to use NTP (Network Time Protocol) select "Yes".

Select a public NTP server close to where you live for the best outcome. I live in the United States so I set my NTP server to "0.us.pool.ntp.org".

Set the time zone you live in. I selected "Eastern" since I live in the Eastern time zone.

The installer will detect the disks connected to the system.

Partitioning the disks will allow us to divide the hard disk into sections. I select "Guided - use entire disk" here to install on my empty 500GB hard drive.

It displays I have one 500GB drive installed in the system.

Select the partitioning scheme you wish to use here. I recommend separating /home, /var, and /tmp partitions to for the following reasons.

Separate data that needs backing up such as /home to make things easier.
Isolate parts of the file system to increase security.
Restrict the growth of a file system. If /var is filled it will not fill the whole disk.

After the guided partitions are created select "Finish partitioning and write changes to disk".

The changes will be displayed to make sure that is how you want it. Select "Yes" to write the changes to disk.

Install the packages for the base system.

Select a kernel to install in the system. linux-image-amd64 is the kernel generic package.
linux-image-5.10.0-8-amd64 will just specify the exact version.

Select "generic: include all available drivers" to make sure you install the drivers you need.

Configure the package manager.

This option allows you to scan for extra installation media such as a DVD. We only have the USB we are using to install the operating system. Select "No" to scan extra installation media. Extra programs can be installed from a network mirror.

Select "Yes" to use a network mirror. This will connect us to a online repository to access more software than what is on the installation USB.

Select "http".

Pick a network mirror that is closest to you for the fastest download.

Leave HTTP proxy information blank and select "Continue" unless you know you are using a proxy.

Select use "non-free" software. Recommended for a desktop/laptop.

Source repositiories in APT will allow you to download the source code for packages. You can select "No" here. This can be enabled easily in /etc/apt/sources.list later if you want.

It is recommended to install security updates. Click "Continue".

Select and install software.

It is your choice to have security updates installed automatically using the unattended-upgrades package. The default setting is to not run automatic security updates.

You can join the package survey if you wish here.

For a minimal Debian install I have deselected everything here except for "standard system utilities". This will provide you with a lean system that is not resource hungry. Remember other packages can be installed later.

Install GRUB to the boot loader of the hard disk.

Select "Yes" to install GRUB to the primary drive.

I have one drive in the computer, /dev/sda. I will select that option instead of entering it manually.

Select "Yes" to force GRUB installation to the EFI removable media path to a fallback location just in case the EFI firmware does not meet the EFI specification.

Click "Enter" to finish the installation.

Click "Yes" to set the system clock to UTC.

If you wanted to set up a server, once you get to this point reboot the computer and your Debian installation is finished.

If you only wanted a minimal server you are done with the installation process. Click "Continue" to reboot. Remember to remove the USB flash drive installation media. Upon reboot you will be presented with this splash screen.

How to add a desktop environment

If you wanted a graphical user interface sign in and install the desktop of your choice. You have many desktop options such as Xfce, Gnome, KDE, Mate, LXDE. See task-xfce-desktop task-gnome-desktop task-kde-desktop etc.

To install the Xfce desktop run these commands.



$ sudo apt update

$ sudo apt upgrade

$ sudo apt install task-xfce-desktop 

$ sudo systemctl reboot

After logging in you will be presented with the Xfce desktop.

Conclusion

I have shown you how to expert install of Debian 11 Bullseye step by step.
You will be now able to use Debian's flexible installer to install a minimal server or a desktop/laptop.

Thank you for reading my article.

Follow me on Dev.to and Github.

Please feel free to leave comments, questions, and suggestions.

How To Use Vim Mode On The Command Line In Bash

brandon_wallace — Fri, 11 Jun 2021 03:02:33 +0000

Introduction

Learn how to use Vi mode on the command line in Bash.

Vim lovers rejoice.

Did you know you can use Vim mode on the command line?

After I found out you could enable Vim mode in bash
set -o vi is always the first line I add to by .bashrc.

In this article I will go over

Movement
Editing
Searching

By default, the Bash command line uses Emacs style keyboard shortcuts, such as CTRL+A to go to the beginning of the line and CTRL+E to go to the End of the line.

Here is a small table that shows a comparison of the Emacs style keyboard shortcuts and the Vim equivalent on the command line.

Emacs	Vim	Result
Ctrl+A	0	Move cursor to beginning of line.
Ctrl+E	$	Move cursor to end of line.
Alt+B	b	Move cursor back one word.
Alt+F	w	Move cursor right one word.
Ctrl+B	h	Move cursor back one character.
Ctrl+F	l	Move cursor right one character.
Ctrl+P	k	Move up in Bash command history.
Ctrl+R	j	Move down in Bash command history.

Add this line to the bottom of your .bashrc file.



set -o vi

Source your .bashrc file to make the changes take effect.



$ source ~/.bashrc

After adding that line and sourcing the .bashrc file, you now have Vim commands available on the Bash command line.

You can perform a variety of commands Vim users are used to on the command line.

If you are a Vim user already you know about command mode and insert mode. By default, in the Bash command line you are in insert mode.

You must press ESC to enter command mode.

By the way, I am currently using Bash version 5.2.9.



$ bash --version | head -1

GNU bash, version 5.2.9(1)-release (x86_64-pc-linux-gnu)

Movement

This is how you move around.

Out of the four Vim movement keys h j k l only h and l work to move the cursor left and right.

First press the ESC key to make sure you are in command mode.

$ Move the cursor to the end of the line.

0 Move the cursor to the beginning of the line.

W Move to the next word using space character as the delimiter.

w Move to the next word or special character.

B Move back one word using space character as the delimiter.

b Move back one word or special character.

^ Move to the first non-blank character at the beginning of the line.

f<character> Find occurrence of the next character.

Examples

ft finds the next occurrence of the letter t.

f" finds the next occurrence of the double quote character ".

; Press semi-colon to move to the next occurrence of the character.

F<character> Performs a backward search for a character.

Examples

Ft finds the next occurrence of the letter t backward search.

F" finds the next occurrence of the double quote character " backward search.

; Press semi-colon to move to the next occurrence of the character.

Editing

This is how you edit text.

x Delete a single character under cursor.

X Delete the previous character.

I Enter insert mode with the cursor at the start of the line.

A Enter insert mode at the end of the line to append text.

cc Change the whole line. The whole line is deleted and puts you in insert mode.

C Change text from the cursor to the end of the line.

ea Move cursor to the end of the word and enter insert mode to append text.

y Yank (copy) word under cursor.

Y Yank (copy) from the cursor to the end of the line.

p or P Paste the text you copied.

r Replace the single character under the cursor.

R Replace the characters under the cursor as you type.
This is like pressing the insert key on the keyboard while in a document editing program such as Libreoffice or Microsoft Word.

. Repeat the last command by pressing the period character. This is one of the most useful commands in Vim.

u Undo last command. You can press this key multiple times to go back in time.

~ Toggle the case of the letter under the cursor.

dd or D To delete the whole line.

dw Delete current word under cursor.

d3w Delete three words.

c2w Change two words. This deletes two words and puts you in insert mode.

y2w Yank (copy) two words.

xp Transpose letters.

Searching

This is how you search for a previous run command.

You can search for commands by pressing forward slash / and typing a part of a command you ran.
It will find the last command you ran with the matching string.

I want to search for the last gunicorn command so I type /gunicorn and press ENTER.

Conclusion

If you enjoy using the Vim text editor you will be happy to know that you can also use a few Vim commands on the command line.

View my .vimrc file.

Follow me on Github and DEV.to.

Top Firefox Extensions For Developers 🔥🚀

brandon_wallace — Sun, 07 Mar 2021 13:54:07 +0000

Article No Longer Available

Here are some great Firefox extensions for developers which will make you more productive.

1 - Wappalyzer

Wappalyzer will identify technologies used on websites.

2 - Stylus

Use Stylus to redesign, edit, create, and manage a website's CSS.

3 - JSON View

View JSON document in the browser formatted and highlighted.

4 - HTML Validator

Validate HTML on a webpage.

5 - Measure-it

Measure elements on the webpage.

6 - REST Client

Make custom HTTP request for testing purposes.

7 - ColorZilla

Many features related to selecting colors.

8 - Selenium IDE

Extension that allows you to record, edit, and debug tests.

9 - Web Developer

Add various web developer tools to your browser.

10 - WhatFont

Inspect fonts contained on a page.

Comment on your favorite extension!

Linked article: Go check out this awesome list of Chrome extensions by DevLorenzo 🚀

Article No Longer Available

Cover image by Gerd Altmann on Pixabay

Show Off Your Mechanical Keyboard

brandon_wallace — Mon, 01 Mar 2021 03:26:44 +0000

Mechanical keyboards have become extremely popular during the last few years.
Many people find the experience of typing on a mechanical keyboard highly enjoyable compared to that of typing on the common membrane keyboard.
Mechanical keyboards come in all shapes, sizes, and colors and some of the mechanical keyboards are customizable. Some people are even building their own mechanical keyboards. I have seen people that have gone to great lengths to customize their keyboards with stunning results.

Even cats are fans of mechanical keyboards.

My mechanical keyboard

Here is an image my mechanical keyboard. When I was searching for a mechanical keyboard my only requirements were blank keys and to have the escape key be red. Blank keys really assist a person in becoming a touch typist (with the blank keys actually I have no issues typing passwords.)

Specifications:

Size: 100% Full size 104 keys (445 x 142 x 30mm)
Switches: Cherry MX Brown switches
Cable: Braided non-removable USB cable
Weight: 1088g (2.4lbs)
Backlighting: none

Tell us:

How has your experience been typing on a mechanical keyboard?
What kind of switches do you have?
What keyboard layout do you use?
What size keyboard do you prefer?

Make Your Tmux Status Bar 100% Better With Bash

brandon_wallace — Sat, 20 Feb 2021 23:02:33 +0000

This article has been re-written

Make Your Status Line 100% Better With Bash

Did you know that you can easily have a Bash script display information on the Tmux status bar? Because of that the possibilities are almost endless. You can display all sorts of valuable information such as:

Included in this article:

Hostname
IP address
Netmask
Memory usage
Memory total
CPU temperature
System load
Battery meter
VPN status
Time
Date

Not included in article:

Weather report
Gateway
Git status

I will show you how to create a modular Bash script to display useful information in the status bar. There are a lot of plug-ins you could install for Tmux but engineering things yourself is a lot of fun. I will create a separate function for each status bar item to make the script modular, that way we will only call the functions that we need.

Here is the default status bar.

Here is the status bar customized.

Requirments

lm-sensors
bc
acpi

Check your Tmux version. I am using version 3.1.



$ tmux -V

# Output
tmux 3.1c

If you do not have a .tmux.conf create one in your home directory.



$ touch .tmux.conf

In the .tmux.conf make sure you have the following lines.



# Status bar
set -g status on
set -g status-interval 1
set -g status-justify centre # Careful! It is spelled centre not center.
set -g status-style fg=white,bg=black

# Highlight the current window.
setw -g window-status-current-style fg=white,bg=red,bright

# Status Bar Left side
set -g status-left-length 50
set -g status-left-style default
set -g status-left "#h #( ~/.tmux/left_status.sh )"

# Status Bar Right side
set -g status-right-length 40
set -g status-right-style default
set -g status-right "#( ~/.tmux/right_status.sh )"

Make a hidden folder in your home directory to save your Bash scripts.



$ mkdir .tmux

Make two Bash scripts, one for the left side, one for the right.



$ touch ~/.tmux/right_status.sh
$ touch ~/.tmux/left_status.sh

The scripts are currently not executable ( rw-r--r-- ).



$ ls -lF ~/.tmux/*.sh
-rw-r--r-- 1 bw bw    0 Feb 19 18:44 /home/bw/.tmux/right_status.sh
-rw-r--r-- 1 bw bw    0 Feb 19 18:44 /home/bw/.tmux/left_status.sh

Make the scripts executable so they will run the chmod command.



$ chmod +x ~/.tmux/right_status.sh
$ chmod +x ~/.tmux/left_status.sh

The scripts are now executable ( rwxr-xr-x ).



$ ls -lF ~/.tmux/*.sh
-rwxr-xr-x 1 bw bw    0 Feb 19 18:44 /home/bw/.tmux/right_status.sh*
-rwxr-xr-x 1 bw bw    0 Feb 19 18:44 /home/bw/.tmux/left_status.sh*

Status Bar Left Side

First edit the left_status.sh script. Add the following content. The ip_address function displays the IP address and netmask.

$ vim ~/.tmux/left_status.sh



#!/bin/bash


function ip_address() {

    # Loop through the interfaces and check for the interface that is up.
    for file in /sys/class/net/*; do

        iface=$(basename $file);

        read status < $file/operstate;

        [ "$status" == "up" ] && ip addr show $iface | awk '/inet /{printf $2" "}'

    done

}

Underneath the IP address function add the CPU function. You must install lm-sensors for this to work. Run these two commands.



$ sudo apt install lm-sensors

$ sudo sensors-detect

Run the sensors command to see the output.



# Celcius

$ sensors

# Output
acpitz-acpi-0
Adapter: ACPI interface
temp1:        +27.8°C  (crit = +105.0°C)
temp2:        +29.8°C  (crit = +105.0°C)

# Fahrenheit

$ sensors -f

# Output
acpitz-acpi-0
Adapter: ACPI interface
temp1:        +82.0°F  (crit = +221.0°F)
temp2:        +85.6°F  (crit = +221.0°F)

Add the cpu_temperature function below the ip_address function.



function cpu_temperature() {

    # Display the temperature of CPU core 0 and core 1.
    sensors -f | awk '/Core 0/{printf $3" "}/Core 1/{printf $3" "}'

}

To see the memory usage we will add a memory_usage function. We need the bc command to calculate the percentage of memory used.

Install bc command.



$ sudo apt install bc

Add the memory_usage function to the script.



function memory_usage() {

    if [ "$(which bc)" ]; then

        # Display used, total, and percentage of memory using the free command.
        read used total <<< $(free -m | awk '/Mem/{printf $2" "$3}')
        # Calculate the percentage of memory used with bc.
        percent=$(bc -l <<< "100 * $total / $used")
        # Feed the variables into awk and print the values with formating.
        awk -v u=$used -v t=$total -v p=$percent 'BEGIN {printf "%sMi/%sMi %.1f% ", t, u, p}'

    fi

}

The next function will display if the VPN is up by checking for the tun0 interface.



function vpn_connection() {

    # Check for tun0 interface.
    [ -d /sys/class/net/tun0 ] && printf "%s " 'VPN*'

}

To complete the left_status.sh script we will use a main function to call the other functions.



function main() {

    # Comment out any function you do not need. 
    ip_address
    cpu_temperature
    memory_usage
    vpn_connection

}

# Calling the main function which will call the other functions.
main

Status Bar Right Side

Now let’s configure the right side.

$ vim ~/.tmux/right_status.sh

The battery meter function displays the level of the battery and changes color depending on the battery level.
We need the acpi program for this.



$ apt install acpi

Run acpi to see the output.



$ acpi

# Output
Battery 0: Unknown, 96%

If your terminal supports emojis you can add an emoji to the status bar.

I will add the lighting bolt emoji to show when the battery is charging.

Add the battery_meter function to the Bash script.

$ vim ~/.tmux/right_status.sh



#!/bin/bash

function battery_meter() {

    if [ "$(which acpi)" ]; then

        # Set the default color to the local variable fgdefault.
        local fgdefault='#[default]'

        if [ "$(cat /sys/class/power_supply/AC/online)" == 1 ] ; then

            local icon='🗲'
            local charging='+' 

        else

            local icon=''
            local charging='-'

        fi

        # Check for existence of a battery.
        if [ -x /sys/class/power_supply/BAT0 ] ; then

            batt0=$(acpi -b 2> /dev/null | awk '/Battery 0/{print $4}' | cut -d, -f1)

            case $batt0 in

                # From 100% to 75% display color grey.
                100%|9[0-9]%|8[0-9]%|7[5-9]%) fgcolor='#[fg=brightgrey]' 
                    ;;

                # From 74% to 50% display color green.
                7[0-4]%|6[0-9]%|5[0-9]%) fgcolor='#[fg=brightgreen]' 
                    ;;

                # From 49% to 25% display color yellow.
                4[0-9]%|3[0-9]%|2[5-9]%) fgcolor='#[fg=brightyellow]' 
                    ;;

                # From 24% to 0% display color red.
                2[0-4]%|1[0-9]%|[0-9]%) fgcolor='#[fg=brightred]'
                    ;;
            esac

            # Display the percentage of charge the battery has.
            printf "%s " "${fgcolor}${icon}${charging}${batt0}%${fgdefault}"

        fi
    fi
}

The next function will add to the script is to get the load average using the uptime command.



function load_average() {

    printf "%s " "$(uptime | awk -F: '{printf $NF}' | tr -d ',')"

}

To see the time, date, and timezone add the date_time function to the Bash script.



function date_time() {

    printf "%s " "$(date +'%Y-%m-%d %H:%M:%S %Z')"

}

The last function is the main function which calls the other functions.



function main() {

    battery_meter
    load_average
    date_time

}

# Calling the main function which will call the other functions.
main

Complete Scripts

$ cat ~/.tmux/left_status.sh



#!/bin/bash


function ip_address() {

    # Loop through the interfaces and check for the interface that is up.
    for file in /sys/class/net/*; do

        iface=$(basename $file);

        read status < $file/operstate;

        [ "$status" == "up" ] && ip addr show $iface | awk '/inet /{printf $2" "}'

    done

}

function cpu_temperature() {

    # Display the temperature of CPU core 0 and core 1.
    sensors -f | awk '/Core 0/{printf $3" "}/Core 1/{printf $3" "}'

}

function memory_usage() {

    if [ "$(which bc)" ]; then

        # Display used, total, and percentage of memory using the free command.
        read used total <<< $(free -m | awk '/Mem/{printf $2" "$3}')
        # Calculate the percentage of memory used with bc.
        percent=$(bc -l <<< "100 * $total / $used")
        # Feed the variables into awk and print the values with formating.
        awk -v u=$used -v t=$total -v p=$percent 'BEGIN {printf "%sMi/%sMi %.1f% ", t, u, p}'

    fi

}

function vpn_connection() {

    # Check for tun0 interface.
    [ -d /sys/class/net/tun0 ] && printf "%s " 'VPN*'

}

function main() {

    # Comment out any function you do not need. 
    ip_address
    cpu_temperature
    memory_usage
    vpn_connection

}

# Calling the main function which will call the other functions.
main

$ cat ~/.tmux/right_status.sh



#!/bin/bash

function battery_meter() {

<span class="k">if</span> <span class="o">[</span> <span class="s2">"</span><span class="si">$(</span>which acpi<span class="si">)</span><span class="s2">"</span> <span class="o">]</span><span class="p">;</span> <span class="k">then</span>

    <span class="c"># Set the default color to the local variable fgdefault.</span>
    <span class="nb">local </span><span class="nv">fgdefault</span><span class="o">=</span><span class="s1">'#[default]'</span>

    <span class="k">if</span> <span class="o">[</span> <span class="s2">"</span><span class="si">$(</span><span class="nb">cat</span> /sys/class/power_supply/AC/online<span class="si">)</span><span class="s2">"</span> <span class="o">==</span> 1 <span class="o">]</span> <span class="p">;</span> <span class="k">then

        </span><span class="nb">local </span><span class="nv">icon</span><span class="o">=</span><span class="s1">'🗲'</span>
        <span class="nb">local </span><span class="nv">charging</span><span class="o">=</span><span class="s1">'+'</span> 

    <span class="k">else

        </span><span class="nb">local </span><span class="nv">icon</span><span class="o">=</span><span class="s1">''</span>
        <span class="nb">local </span><span class="nv">charging</span><span class="o">=</span><span class="s1">'-'</span>
    <span class="k">fi</span>

    <span class="c"># Check for existence of a battery.</span>
    <span class="k">if</span> <span class="o">[</span> <span class="nt">-x</span> /sys/class/power_supply/BAT0 <span class="o">]</span> <span class="p">;</span> <span class="k">then

        </span><span class="nb">local </span><span class="nv">batt0</span><span class="o">=</span><span class="si">$(</span>acpi <span class="nt">-b</span> 2&gt; /dev/null | <span class="nb">awk</span> <span class="s1">'/Battery 0/{print $4}'</span> | <span class="nb">cut</span> <span class="nt">-d</span>, <span class="nt">-f1</span><span class="si">)</span>

        <span class="k">case</span> <span class="nv">$batt0</span> <span class="k">in</span>

            <span class="c"># From 100% to 75% display color grey.</span>
            100%|9[0-9]%|8[0-9]%|7[5-9]%<span class="p">)</span> <span class="nv">fgcolor</span><span class="o">=</span><span class="s1">'#[fg=brightgrey]'</span> 
                <span class="p">;;</span>

            <span class="c"># From 74% to 50% display color green.</span>
            7[0-4]%|6[0-9]%|5[0-9]%<span class="p">)</span> <span class="nv">fgcolor</span><span class="o">=</span><span class="s1">'#[fg=brightgreen]'</span> 
                <span class="p">;;</span>

            <span class="c"># From 49% to 25% display color yellow.</span>
            4[0-9]%|3[0-9]%|2[5-9]%<span class="p">)</span> <span class="nv">fgcolor</span><span class="o">=</span><span class="s1">'#[fg=brightyellow]'</span> 
                <span class="p">;;</span>

            <span class="c"># From 24% to 0% display color red.</span>
            2[0-4]%|1[0-9]%|[0-9]%<span class="p">)</span> <span class="nv">fgcolor</span><span class="o">=</span><span class="s1">'#[fg=brightred]'</span>
                <span class="p">;;</span>
        <span class="k">esac</span>

        <span class="c"># Display the percentage of charge the battery has.</span>
        <span class="nb">printf</span> <span class="s2">"%s "</span> <span class="s2">"</span><span class="k">${</span><span class="nv">fgcolor</span><span class="k">}${</span><span class="nv">charging</span><span class="k">}${</span><span class="nv">batt0</span><span class="k">}</span><span class="s2">%</span><span class="k">${</span><span class="nv">fgdefault</span><span class="k">}</span><span class="s2">"</span>

    <span class="k">fi
fi</span>



}

function load_average() {

<span class="nb">printf</span> <span class="s2">"%s "</span> <span class="s2">"</span><span class="si">$(</span><span class="nb">uptime</span> | <span class="nb">awk</span> <span class="nt">-F</span>: <span class="s1">'{printf $NF}'</span> | <span class="nb">tr</span> <span class="nt">-d</span> <span class="s1">','</span><span class="si">)</span><span class="s2">"</span>



}

function date_time() {

<span class="nb">printf</span> <span class="s2">"%s"</span> <span class="s2">"</span><span class="si">$(</span><span class="nb">date</span> +<span class="s1">'%Y-%m-%d %H:%M:%S %Z'</span><span class="si">)</span><span class="s2">"</span>



}

function main() {

battery_meter
load_average
date_time



}

# Calling the main function which will call the other functions.

main

Conclusion

You can now easily have a Bash script display useful information on the Tmux status bar. I hope you enjoyed reading this article.

Follow me on Dev.to and Github.

Feel free to leave comment, questions, and suggestions.

One-To-Many Database Relationships Complete How To

brandon_wallace — Thu, 18 Feb 2021 22:33:59 +0000

INTRODUCTION

In this article I will show you how to set up a one-to-many database relationship, how you would know when you would need to use one, as well as some example queries.

We will use:

Python 3.9+
PostgreSQL (database)
Flask (framework)
Flask-SQLAlchemy (object-relation mapper)
Pipenv (virtual environment)

Once your C.R.U.D. ( Create Read Update Delete ) applications start getting more complex, you will find that you need to link tables together within the database. In databases it is very common task to create relationships between tables. A one-to-many relationship is a method that will allow you to link a parent to a child table in a database. A one-to-many relationship is created by adding a foreign key to the child table.

Diagram created on diagrams.net

PK = primary key

FK = foreign key

WHEN WOULD I USE A ONE-TO-MANY RELATIONSHIP?

Let me present to you a real-world scenario, let’s say you have an online store and you need to keep track of your customers and the orders they make. In your database you would create a table for customers and separate table for the orders. How would you know which order belongs to which customer? The way to do that is to set up a one-to-many relationship. This will allow you to take one customer and query all the information connected to the orders the customer made.

I will show you an easy way to know when you need to set up a one-to-many database relationship as opposed to a one-to-one or a many-to-many database relationship. Going back to the example of the online store, you have two tables, a customer table and an order table. You would ask yourself two questions about the tables.

Example 1:

Q: Does a customer have many orders?
A: Yes, a customer can have many orders.

Q: Does an order have many customers?
A: No, only one person can create an order.

We have one customer and many orders but it does not work the other way around. One order does not have many customers. We can clearly see that example 1 is a great candidate for a one-to-many database relationship.

Let’s look at another example.

Example 2:

In another imaginary database we have a table for students and a table for classes. So we form the questions like this.

Q: Does a student have many classes?
A: Yes, a student can have many classes.

Q: Does a class have many students?
A: Yes, a class can have many students.

Here we have many students and many classes because of that, example 2 is not suitable for a one-to-many relationship.

How To Set Up The Project

Install PostgreSQL and Pip. We use Pip to install Pipenv.

$ sudo apt install postgresql libpq-dev python3-pip

Enable and start PostgreSQL.

$ sudo systemctl enable postgresql

$ sudo systemctl start postgresql

Check to see if PostgreSQL is running.

$ sudo systemctl status postgresql
● postgresql.service - PostgreSQL RDBMS
   Loaded: loaded (/lib/systemd/system/postgresql.service; enabled; vendor preset: enabled)
   Active: active (exited) since Mon 2021-02-01 10:09:46 EST; 2h 56min ago
   Process: 920 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
   Main PID: 920 (code=exited, status=0/SUCCESS)
[...]

$ sudo su – postgres

postgres@laptop:~$ psql

postgres=#

Check the PostgreSQL version.

postgres=# SELECT version();
                                                     version                                                      
------------------------------------------------------------------
 PostgreSQL 14.1 (Debian 14.1-1.pgdg110+1) on x86_64-pc-linux-gnu [...]

Set the postgres user’s password. Please use something stronger than 123456.

postgres=# ALTER USER postgres WITH PASSWORD '123456'; 
ALTER ROLE

Create a database called mystoredb.

postgres=# CREATE DATABASE mystoredb;
CREATE DATABASE

List the databases. You will see mystoredb on the list.

postgres=# \l
                                  List of databases
   Name    |  Owner   | Encoding |   Collate   |    Ctype    |   Access privileges   
-----------+----------+----------+-------------+-------------+-----------------------
 mystoredb | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | 
 postgres  | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | 
 template0 | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
[...]

Exit psql interactive terminal and logout as the postgres user.

postgres=# \q

postgres@laptop:~$ exit

Create a directory for your project.

$ mkdir my_project/

$ cd my_project/

Install pipenv using pip3.

$ pip3 install pipenv

Start the Python virtual environment.

$ pipenv shell

Install the required libraries.

$ pipenv install flask flask-sqlalchemy psycopg2-binary

Here is a simple example of a one-to-many relationship with Flask-SQLAlchemy.

class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    comment_id = db.relationship('Comment', cascade='all, delete', backref='author' lazy=True)

class Comment(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    post_id = db.Column(db.Integer, db.ForeignKey('post.id'))

db.relationship()

This function looks at the child table and pulls up multiple instances of the child table.

backref

Backref creates a kind of invisible column within the child table.

lazy

Lazy defines when the data will be pulled from the database.

lazy=select
or
lazy=True

This is the default setting. SQLAlchemy will load the all data necessary at once.

db.ForiegnKey()

This function specifies the parent class (written in lowercase) and relates items back to the parent table.

Create file called application.py and add the following content.

$ vim application.py

# application.py

from datetime import datetime
from flask import Flask
from flask_sqlalchemy import SQLAlchemy


app = Flask(__name__)

app.config['DEBUG'] = True
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://postgres:123456@127.0.0.1:5432/mystoredb'

db = SQLAlchemy(app)


class Customer(db.Model):
    '''Customer table'''

    __tablename__ = 'customer'
    id = db.Column(db.Integer, primary_key=True)
    customer_name = db.Column(db.String(25))
    customer_email = db.Column(db.String(100), nullable=True)
    order_id = db.relationship('Order', cascade='all, delete', backref='customer', lazy=True)

    def __init__(self, customer_name, customer_email):
        self.customer_name = customer_name
        self. customer_email = customer_email

    def __repr__(self):
        return f'<Customer: {self.id} {self.customer_name}>'


class Order(db.Model):
    '''Order table'''

    __tablename__ = 'order'
    id = db.Column(db.Integer, primary_key=True)
    order_date = db.Column(db.DateTime, default=datetime.now)
    # Use datetime to generate a random 6 digit number from milliseconds.
    order_number = db.Column(db.Integer, default=datetime.now().strftime("%f"))
    customer_id = db.Column(db.Integer, db.ForeignKey('customer.id'))

    def __repr__(self):
        return f'<OrderID: {self.id}>'


if __name__ == '__main__':
    app.run(debug=True)

*NOTE:

The syntax for the SQLALCHEMY_DATABASE_URI variable is

'postgresql://<db_username>:<password>@<ip_address>:<port>/<database_name>'

Example of what I am using in this tutorial:

'postgresql://postgres:123456@127.0.0.1:5432/mystoredb'

Change the values of the database URI to reflect your set up.

Start a Python interpreter shell on the command line.

$ python3

Import the database + models and create the tables.

>>> from application import db, Customer, Order

>>> db.create_all()

Add a few people to the customer table.

>>> brandon = Customer(customer_name='Brandon', customer_email='brandon@example.com')
>>> maria = Customer(customer_name='Maria', customer_email='maria@example.com')
>>> ahmed = Customer(customer_name='Ahmed', customer_email='ahmed@example.com')
>>> cheuk = Customer(customer_name='Cheuk', customer_email='cheuk@example.com')
>>> nikolaus = Customer(customer_name='Nikolaus', customer_email='nikolaus@example.com')

Add all people to the database session.

>>> db.session.add_all([brandon, maria, ahmed, cheuk, nikolaus])

Commit all changes to the database to save the users.

>>> db.session.commit()

Create orders and link them with customers in the database like this. Remember 'customer' is the backref value in the parent table.

>>> order1 = Order(customer=brandon)
>>> order2 = Order(customer=brandon)
>>> order3 = Order(customer=brandon)
>>> order4 = Order(customer=ahmed)
>>> order5 = Order(customer=ahmed)
>>> order6 = Order(customer=cheuk)
>>> order7 = Order(customer=cheuk)
>>> order8 = Order(customer=maria)
>>> order9 = Order(customer=nikolaus)

Add all orders to the session.

>>> db.session.add_all([order1, order3, order3, order4, order5, order6, order7, order8, order9])

Commit all changes to the database to save the orders.

>>> db.session.commit()

How To Perform Queries

At this point we can query the database.

Pull up all the customer records in the database and loop through the results.

>>> customers = Customer.query.all()

>>> for person in customers:
...     f'ID: {person.id} Name: {person.customer_name} Email: {person.customer_email}'
... 
'ID: 1 Name: Brandon Email: brandon@example.com'
'ID: 2 Name: Maria Email: maria@example.com'
'ID: 3 Name: Ahmed Email: ahmed@example.com'
'ID: 4 Name: Cheuk Email: cheuk@example.com'
'ID: 5 Name: Nikolaus Email: nikolaus@example.com'

Extract the name like this.

>>> for customer in customers:
...     customer.customer_name
... 
'Brandon'
'Maria'
'Ahmed'
'Cheuk'
'Nikolaus'

Get the total order count for Brandon.

>>> brandon_order_count = Order.query.filter_by(customer_id=1).count()

>>> f'Total orders for Brandon: {brandon_order_count}'
Total orders for Brandon: 3

Get the order numbers for Brandon.

>>> brandon_all_orders = Order.query.filter(Order.customer_id == 1).all()

>>> for order in brandon_all_orders:
...     f'Order number: {order.order_number}'
... 
'Order number: 680018'
'Order number: 193492'
'Order number: 662450'

Get the orders from Brandon sorted by most recent.

>>> latest_orders = Order.query.order_by(Order.order_date.desc()).all()

>>> for order in latest_orders:
...     order.order_date.strftime("%Y-%m-%d %H:%M")
... 
'2022-04-03 18:09'
'2022-02-02 20:22'
'2022-01-01 10:59'

Get the orders from Brandon sorted by oldest first.

>>> oldest_orders = Order.query.order_by(Order.order_date.desc()).all()

>>> for order in oldest_orders:
...     order.order_date.strftime("%Y-%m-%d %H:%M")
... 
'2022-01-01 10:59'
'2022-02-02 20:22'
'2022-04-03 18:09'

Get orders filtering by a before a specific date.

>>> from datetime import datetime
>>> from_date = datetime(year=2022, month=2, day=22)

>>> befor_feb_22 = Order.query.filter(Order.order_date <= from_date).all()

>>> for order in before_feb_22:
...     f'ID: {order.id} Date: {order.order_date} OrderNum: {order.order_number} CustID: {order.customer_id}'
... 
'ID: 2 Date: 2022-01-01 10:29:43.380762 OrderNum: 27227 CustID: 1'
'ID: 1 Date: 2022-02-02 10:29:43.380762 OrderNum: 27227 CustID: 1'

Get orders filtering by a after a specific date.

>>> after_date = datetime(year=2022, month=2, day=22)
>>> after_feb_22 = Order.query.filter(Order.order_date >= after_date).all()

>>> for order in after_feb_22:
...     f'ID: {order.id} Date: {order.order_date} OrderNum: {order.order_number} CustID: {order.customer_id}'
... 
'ID: 3 Date: 2022-04-03 10:29:43.380762 OrderNum: 27227 CustID: 1'

Get the date and time Cheuk placed the orders.

>>> cheuk_all_orders = Order.query.filter(Order.customer_id == 4).all()

>>> for order in cheuk_all_orders:
...     f'Order date: {order.order_date.strftime("%Y-%m-%d %H:%M")}'
... 
'Order date: 2022-02-07 19:52'
'Order date: 2022-02-07 21:38'

>>> exit()

How To Troubleshoot If You Have Issues

Check carefully for syntax errors.
If you ran db.create_all() with errors in the application.py file you might have to delete the database and recreate it.

$ sudo su – postgres

postgres=# DROP DATABASE mystoredb;
DROP DATABASE

postgres=# CREATE DATABASE mystoredb;
CREATE DATABASE

Then run db.create_all() again to create the tables.

>>> python3

>>> from application import db, Customer, Order

>>> db.create_all()

Feel free to leave comments, questions, and suggestions.

Set Up A GIT Server The Easy Way!

brandon_wallace — Sun, 07 Feb 2021 02:35:19 +0000

Introduction

In this tutorial I will show you step-by-step how to set up a local Git server. This is an easy and fun project that is great for a home server, a low-powered single board computer such as a Beaglebone Black or Raspberry Pi, or even a Virtual Private Server. All you need is Git installed on the server and an SSH key on the client computer.

The benefit to this is that are you will have your own private git server you control, where you can push, pull, and clone repositories from.

Let’s begin…

On the server

First thing is to log into the server and install Git.

For an .deb based system run.



$ sudo apt update

$ sudo apt install git

For an .rpm based system run.



$ sudo yum install git

OR

$ sudo dnf install git

The next step is to create a git user.



$ sudo useradd -r -m -U -s /bin/bash git

-r

creates a system user

-m

creates a home directory

-U

create a group name the same as the username.

-s /path/to/shell

Set the default shell for the user.

You should see the git user's home directory created under /home.



$ ls -lF /home/
total 8
drwxr-xr-x  2 git git 4096 Jan 29 20:09 git/

Set a password for the git user.



$ sudo passwd git

Switch accounts to become the git user.



$ su - git

Create a .ssh directory in the git user’s home folder.



$ mkdir /home/git/.ssh

You will see that the default permissions are 0755 (drwxr-xr-x).



$ ls -ld /home/git/.ssh
drwxr-xr-x 2 git git 4096 Jan 29 20:25 /home/git/.ssh

We need to set the permissions on the .ssh directory to 0700 so that SSH will function correctly. We will set the directory permission to 0700 (drwx------) with this command.



$ sudo chmod 0700 /home/git/.ssh

Verifying the permissions are set correctly by running “ls -ld”.



$ ls -ld /home/git/.ssh
drwx------ 2 git git 4096 Jan 29 20:25 /home/git/.ssh

Let create our first repository on the server. By convention we append .git to the end of the directory name. This reminds us that the directory is a repository and not a regular directory.



$ git init --bare my_project.git

Nice! Let’s work on the client computer.

On the client computer

At this time we will create SSH keys with this command.



$ ssh-keygen -t rsa -b 4096 -C “my_email” -f ~/.ssh/id_rsa

-t <type>

Type of key (rsa or dsa). Use rsa.

-b <bits>

Specifies the number of bits in the key to create. Use 4096.

-C “comment”

Add a comment.

-f /path/to/key

Specify the path to the rsa file. It is common to name it id_rsa.

Upon running the command you will see output similar to what is below. Set a password when prompted.



Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase): ************
Enter same passphrase again: ************
Your identification has been saved in .ssh/id_rsa.
Your public key has been saved in .ssh/id_rsa.pub.
The key fingerprint is:
SHA256:Yg5D1kaIN9M6ln3sJlHzEggLoKpDYFkhXFR1ZOwP/sI my_email
The key's randomart image is:
+---[RSA 4096]----+
|oo+*+=ooo+       |
|..=.=+o *.       |
|oo .+*oo.+       |
|+  o=.o +o.      |
|.. .o.o+S.o      |
|o    =..o. .     |
|o     .o. .      |
| .       E .     |
|          .      |
+----[SHA256]-----+

You will see that two files have been created. id_rsa is the private key, id_rsa.pub is the public key. The permissions should be set to 0600 (-rw-------).



$ ls -la .ssh/
total 36
drwx------  2 bw bw 4096 Jan 29 20:43 .
drwxr-xr-x 54 bw bw 4096 Jan 29 13:17 ..
-rw-------  1 bw bw 3414 Jan 29 20:43 id_rsa
-rw-------  1 bw bw  733 Jan 29 20:43 id_rsa.pub

The public key needs to be copied over to the git server. To do that use the ssh-copy-id command. Since my server’s IP address is 192.168.12.34 I run the command like this to copy the public key over to the server. Change the IP address to the IP address of your server.



$ ssh-copy-id -i ~/.ssh/id_rsa.pub git@192.168.12.34

-i /path/to/public_key_file

Specify the path to the public key.

After copying the public key over to the server test logging into the server via SSH. Change the IP address to the IP address of your server.



$ ssh git@192.168.12.34
git@192.168.12.34s password:

Last login: Fri Jan 29 20:35:46 2021 from 192.168.12.100
git@192.168.12.34:~ $

Type exit to disconnect from the server.



git@192.168.12.34:~ $ exit

Now we are ready to connect to the repository that we made earlier on the server. Create a directory of the same name as the repository minus the .git extension. On the server we have a directory called my_project.git so on the client computer you create a directory called my_project/.



$ mkdir my_project/

$ cd my_project/

Add a few of the standard git files.



$ touch readme.md .gitignore LICENSE

Add some content to the readme.md.



$ echo ‘# My First Project!’ >> readme.md

Add all the files to the git staging area so they can be committed.



$ git add --all

Commit the files to git. The -m flag allows you to create a short commit message without opening an editor.



$ git commit -m “First commit”

We need to specify the git server we will be using.
This command will specify a remote git server repository where commits will be stored. The syntax is

$ git remote add <remote_name> git@<server_ip>:<git_repo>

can be whatever label you want. The default <remote_name> you will often see is usually origin. I set my “remote_name” to “local” since I have a local server. Change the IP address to the IP address of your server.



(master)my_project $ git remote add local  git@192.168.12.34:my_project.git

Push the first commit to the server.



(master)my_project $ git push local master

Check your remote servers like this. Right now only one repository is

set up which is called ‘local’.



(master)my_project $ git remote -v
local   git@192.168.12.34:my_project.git (fetch)
local   git@192.168.12.34:my_project.git (push)

Remember that I said we were going to do this the easy way?
Since we have finished the initial set up on the server we can create a new repository from the client computer using SSH. No need to log into the server to create the repository. Here is the workflow for creating a new repository on your Git server.

To run a command on a remote server just append the command you wish to run after the SSH command. This will allow you to run the “git init --bare ” command to create a new repository without logging into the server. Run this command changing the IP address to your server’s IP address.



$ ssh git@192.168.12.34 “git init --bare my_second_project.git”

Check that the directory was created on the server.



~ $ ssh git@192.168.12.34 "ls -lF"
total 8
drwxr-xr-x 7 git git 4096 Feb  5 17:47 my_project.git/
drwxr-xr-x 7 git git 4096 Feb  6 21:48 my_second_project.git/

On the client computer create a directory with the same name as the git repository you created on the server minus the .git extension.

On the server we already have a my_second_project.git directory, so create the my_second_project/ directory on the client computer.



$ mkdir my_second_project/

$ cd my_second_project/

$ touch readme.md .gitignore LICENSE

Add some content to the readme.md.



$ echo ‘# My Second Project!’ >> readme.md

$ git add --all

$ git commit -m “First commit”

$ git remote add local git@192.168.12.34:my_second_project.git

$ git push local master
git@192.168.12.34's password: ************
Enumerating objects: 4, done.
Counting objects: 100% (4/4), done.
Delta compression using up to 2 threads
Compressing objects: 100% (2/2), done.
Writing objects: 100% (4/4), 306 bytes | 306.00 KiB/s, done.
Total 4 (delta 0), reused 0 (delta 0)
To 192.168.12.34:my_project.git
 * [new branch]      master -> master
Branch 'master' set up to track remote branch 'master' from 'local'.

All done.

Just to review, to create a new local repository you simply run the following commands.

Full example:



$ ssh git@192.168.12.34 “git init --bare nodejs_app.git”
$ mkdir nodejs_app/
$ cd nodejs_app/
$ touch readme.md .gitignore LICENSE
$ echo ‘# My Nodejs App’ >> readme.md
$ git init
$ git add --all
$ git commit -m “First commit”
$ git remote add local git@192.168.12.34:nodejs_app.git
$ git push local master

*NOTE:

If you wish to you could easily add a second connection to Github if you want to have that same repository online by running the ‘git remote add' command.
First create a new repository on Github with the same name (my_project) without any files such as the readme.md, .gitignore, or LICENSE because we already created them.

Second run the git remote add command. Here is an example:



(master)my_project $ git remote add origin git@github.com/brandon-wallace:my_project.git

Look at the remote repositories available now.



(master)my_project $ git remote -v
local   git@192.168.12.34:my_project.git (fetch)
local   git@192.168.12.34:my_project.git (push)
origin    git@github.com/brandon-wallace:my_project.git (fetch)
origin    git@github.com/brandon-wallace:my_project.git (push)

Now it shows that I have two git servers I can use, one is called local (my server) the other origin (Github).

BONUS TIP!

After logging into your computer you can use ssh-agent to store the rsa key password so that you do not have to keep typing your SSH private key password every time you do a push to a repository. To store the SSH password run.



$ eval $(ssh-agent -s)

$ ssh-add /home/brandon/.ssh/id_rsa
Enter passphrase for /home/bw/.ssh/id_rsa: ***********
Identity added: /home/bw/.ssh/id_rsa (comment)

See that the environment variable is exists.



$ env | grep SSH

SSH_AUTH_SOCK=/tmp/ssh-08AsdfQWRTYE/agent.69007
SSH_AGENT_PID=69007

Now all your git push commands will not require you typing the password.



$ git push origin master
Enumerating objects: 6, done.
Counting objects: 100% (6/6), done.
Delta compression using up to 2 threads
Compressing objects: 100% (4/4), done.
Writing objects: 100% (4/4), 518 bytes | 518.00 KiB/s, done.
Total 4 (delta 2), reused 0 (delta 0)
To 192.168.12.34:my_project.git
   d06bb48..beee582  master -> master

Feel free to leave comments, questions, and suggestions.

Deploy Flask The Easy Way With Gunicorn and Nginx!

brandon_wallace — Fri, 29 Jan 2021 04:57:12 +0000

Introduction

After creating a Flask application you probably want people to see it. This tutorial will show you how to deploy your Flask application on a Linux server Nginx with Gunicorn.

Requirements

A Server (Debian is used in this tutorial)
Nginx
Gunicorn
Pipenv

The first step in the process is to install pip and pipenv. We will use pipenv to set up the virtual environment.



$ sudo apt update
$ sudo apt upgrade

$ sudo apt install python3-pip pipenv

Check that pipenv installed correctly by checking the version.



$ pipenv --version
pipenv, version 2022.12.19

Create project directory to hold your project. /var/www/ is a good location.



$ sudo mkdir -p /var/www/myproject

The default permissions for the directory are set to root.



$ ls -ld /var/www/myproject
drwxr-xr-x 2 root root 4096 Feb 20 12:37 /var/www/myproject/

Change the permissions for the user and group to your username and the group www-data.



$ sudo chown -R $USER:www-data /var/www/myproject

Check the to see that the permissions changed to username brandon and group name www-data.



$ ls -ld /var/www/myproject
drwxr-xr-x 2 brandon www-data 4096 Jan 27 12:37 /var/www/myproject/

CD into the /var/www/myproject directory.



$ cd /var/www/myproject

Create a .env file to hold the environmental variables.



$ touch .env

Edit the .env file to add the FLASK_APP and FLASK_ENV environmental variables. With any editor add these two lines:

$ vim .env



FLASK_APP=wsgi.py
FLASK_ENV=production

Start the virtual environment. Pipenv will load the variables in the .env file automatically.



$ pipenv shell

Loading .env environment variables...
Loading .env environment variables...
Creating a virtualenv for this project...
Pipfile: /var/www/myproject/Pipfile
Using /usr/bin/python3 (3.11.2) to create virtualenv...
⠇ Creating virtual environment...created virtual environment [...]
✔ Successfully created virtual environment!
Virtualenv location: /home/brandon/.local/share/virtualenvs/myproject-jyD3CuVy
Creating a Pipfile for this project...
Launching subshell in virtual environment...

Use pipenv to install the dependencies.



$ pipenv install flask gunicorn

Loading .env environment variables...
Installing flask...
Installing gunicorn...
Pipfile.lock not found, creating...
[...]

To set up a minimal Flask application create two files application.py and wsgi.py. The main Flask application will be stored in application.py.
wsgi.py will be used to get the application running.



$ touch application.py wsgi.py

Edit application.py file. Add the code for a minimal Flask application with one route for the index page.

$ vim application.py



from flask import Flask

app = Flask(__name__)


@app.route('/')
def index():
    '''Index page route'''

    return '<h1>Application Deployed!</h1>'

Edit the wsgi.py file. Add this code wsgi.py to get the application running.

$ vim wsgi.py



from application import app

if __name__ == '__main__':
    app.run(debug=False)

Let’s test run the Flask application!
Make the Flask application listen on all server interfaces by specifying the address ‘0.0.0.0’.



$ flask run --host '0.0.0.0'

 * Tip: There are .env or .flaskenv files present. Do "pip install python-dotenv" to use them.
 * Serving Flask app 'wsgi.py'
 * Debug mode: off
WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
 * Running on all addresses (0.0.0.0)
 * Running on http://127.0.0.1:5000
 * Running on http://192.168.12.34:5000
Press CTRL+C to quit

Now you can access the application from another computer using a browser, navigate to the server's IP address on port 5000. Make sure port 5000 is not blocked by a firewall so that you will be able to access your Flask application.

Since my server's IP address is 192.168.12.34 I access the Flask application from my laptop with a browser using this address:

http://192.168.12.34:5000

You should see this in the browser.

Press CTRL+C to stop the Flask development server.

It is time to set up Gunicorn!

If you were able to run the Flask development server successfully use this command to test run the application using Gunicorn.



(myproject) $ gunicorn --workers 4 --bind 0.0.0.0:5000 wsgi:app

--workers N

Set the --workers to two times the number of cores in your server. Adjust the number later if you have any issues. Do not exceed 12.

--bind 0.0.0.0:5000

This will listen on all server networking interfaces on port 5000.

wsgi:app

wsgi is the file name without the .py extension. app is the instance of the Flask application within the file. You should see the similar output below.



$ gunicorn --workers 4 --bind 0.0.0.0:5000 wsgi:app

[2024-02-20 20:57:21 -0500] [4936] [INFO] Starting gunicorn 21.2.0
[2024-02-20 20:57:21 -0500] [4936] [INFO] Listening at: http://0.0.0.0:5000 (4936)
[2024-02-20 20:57:21 -0500] [4936] [INFO] Using worker: sync
[2024-02-20 20:57:21 -0500] [4937] [INFO] Booting worker with pid: 4937
[...]

Press CTRL+C to stop the Gunicorn server.

While you are in the virtual environment check the path of gunicorn. Take note of this path. You will need to know the path to gunicorn to configure the systemd service file. My path is /var/www/myproject/.venv/bin/gunicorn your path might be /home/$USER/.local/share/virtualenvs/myproject-544gQc4M/.venv/bin/gunicorn. The path depends if you have PIPENV_VENV_IN_PROJECT=true set in your .bashrc file or not. If the variable is set to true pipenv will use the .venv in your project directory.



$ which gunicorn

/var/www/myproject/.venv/bin/gunicorn

Now that you have a basic Flask application running with Gunicorn we can set up Nginx.

Install Nginx

Run these commands to install and start the Nginx webserver.



$ sudo apt install nginx

$ sudo systemctl enable nginx

$ sudo systemctl start nginx

Check to see if Nginx is running by running this command.



$ sudo systemctl status nginx

● nginx.service - A high performance web server and a reverse proxy server
     Loaded: loaded (/lib/systemd/system/nginx.service; enabled; preset: enabled)
     Active: active (running) since Tue 2024-02-20 21:03:17 EST; 16min ago
       Docs: man:nginx(8)
   Main PID: 5163 (nginx) 
   [...]

Now we create the systemd file that runs Gunicorn as a service. Add the following code but change all paths and user names so that they correspond to your set up. Pay careful attention to the Environment= and ExecStart= variables. The Environment= variable should lead to the bin directory inside your virtual environment. The ExecStart= path should lead where gunicorn is installed in the virtual environment.



$ sudo vim /etc/systemd/system/myproject.service

[Unit]
Description=myproject.service - A Flask application run with Gunicorn.
After=network.target

[Service]
User=brandon
Group=www-data
Environment="PATH=/var/www/myproject/.venv/bin"
WorkingDirectory=/var/www/myproject/
ExecStart=/var/www/myproject/.venv/bin/gunicorn --workers 3 \
--bind unix:/var/www/myproject/myproject.sock wsgi:app

[Install]
WantedBy=multi-user.target

User

Sets the user who has permission to the project directory.

Group

Sets the group who has permission to the project directory.

Environment

Sets the path to the bin directory inside the virtual environment.

WorkingDirectory

Sets the base directory where the code for the project is.

ExecStart

Sets the path to the gunicorn executable inside the virtual environment along with the gunicorn command line options.

Now I enable and start the myproject systemd service.



$ sudo systemctl enable myproject

$ sudo systemctl start myproject

Next we need to create the server block/virtual host in Nginx. Create a file in /etc/nginx/sites-available/ with any editor. Add the following content. Change the name myproject.conf to the name of your project.



$ sudo vim /etc/nginx/sites-available/myproject.conf



server {
        listen 80;
        server_name myproject www.myproject;

        access_log /var/log/nginx/myproject.access.log;
        error_log /var/log/nginx/myproject.error.log;

        location / {
                include proxy_params;
                proxy_pass http://unix:/var/www/myproject/myproject.sock;
        }
}

server_name is where the domain name goes. That is what you will use to access the web application.

access_log and error_logs specify the path to the access and error logs.

location block is where Nginx reverses proxy back to the Flask application.

Enable the website by creating a link to the sites-enabled directory.



$ sudo ln -s /etc/nginx/sites-available/myproject.conf /etc/nginx/sites-enabled/

Make sure the link has been created in sites-enabled directory.



$ ls -l /etc/nginx/sites-enabled/ | grep myproject

lrwxrwxrwx 1 root root 41 Feb 20 17:37 myproject.conf -> /etc/nginx/sites-available/myproject.conf

Check the nginx configuration for errors then restart the service.



$ nginx -t

$ sudo systemctl restart nginx

$ sudo systemctl status nginx

The Flask application is no longer accessible via the IP address since it is now being served by Gunicorn and Nginx. To access the Flask application you would need to use the name you set in the Nginx server block for the directive server_name in the Nginx configuration. To access the web page can edit the host file on your desktop/laptop to point the domain to the IP address of your server.

Edit the host file to add point the domain name to the server.
Since my server's IP address is 192.168.12.34 I would add this line to the host file.

192.168.12.34 myproject www.myproject

Host file location for Linux:
/etc/hosts

Host file location for Windows:
C:\Windows\System32\drivers\etc\hosts

Now I can access the Flask application with a browser via the name.

http://myproject

http://www.myproject

You should seen something similar below.

Troubleshooting

Here are some troubleshooting steps...

For when things do not go right there are a few things you can do to troubleshoot.

It is very important to check carefully for any spelling errors in all the files you edited.

Check systemd.

$ sudo systemctl status myproject.service

$ sudo journalctl -xe

Restart the Gunicorn systemd service.



$ sudo systemctl restart myproject.service
$ sudo systemctl daemon-reload

Add logging to Gunicorn by changing the ExecStart line. Add --error-logfile error.log and --log-level debug to the end of the line.

Change the ExecStart line:



ExecStart=/var/www/myproject/.venv/bin/gunicorn --workers 3 --bind unix:/path/to/myproject/myproject.sock wsgi:app

To this:



ExecStart=/var/www/myproject/.venv/bin/gunicorn --workers 3 --bind unix:/path/to/myproject/myproject.sock wsgi:app --error-logfile error.log --log-level debug

Check the Nginx log files.

$ less /var/www/nginx/error.log

$ less /var/www/myproject/error.log

Check to see if the Nginx server is listening on port 80.



$ ss -lnt | grep 80
LISTEN    0         511                0.0.0.0:80               0.0.0.0:* 
LISTEN    0         511                   [::]:80                  [::]:*

Use curl to check for a 200 OK response.

$ curl -I http://myproject



HTTP/1.0 200 OK

Content-Type: text/html; charset=utf-8

Content-Length: 30

Server: Werkzeug/1.0.1 Python/2.7.16

Date: Wed, 03 Feb 2021 15:18:55 GMT

Conclusion

You have learned to configure Gunicorn to run a Flask application. You learned how to run Gunicorn as a systemd service. You learned to configured a virtual host in Nginx. You should now be able to deploy a Flask application to a server.

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