DEV Community: Eric F 🇺🇦

Create your own memes in Terminal

Eric F 🇺🇦 — Sun, 19 Feb 2023 18:17:56 +0000

To create a “meme”, or just adding text to an image - you don't need an app or an online service. You can do it yourself, in Terminal, using ImageMagick. Here's a short snippet you can use.

Since the command is kind of long, you can save in some file, or make a bash function - or maybe a script.

# ImageMagick v6
$ convert in.jpg -gravity south -font Impact -pointsize 120 -fill white -stroke black -strokewidth 3 -annotate +0+0 'Add text here' out.jpg

# ImageMagick v7
$ magick in.jpg -gravity south -font Impact -pointsize 120 -fill white -stroke black -strokewidth 3 -annotate +0+0 'Add text here' out.jpg

Text position

For -gravity you can use your normal: north, south, center, southeast, etc.

Fonts

I used Impact in the example. It's usally installed. But, if you want to change the font - just use another one from the list of fonts. Most font names are formatted with a dash, like “DevaVu-Sans-Bold”, “NimbusSans-Bold”, etc.

If you try one and it returns an error - you can get the list of fonts (ie. the font names) using:

# ImageMagick v6
$ identify -list font

# ImageMagick v7
$ magick -list font

To get a more readable list, you can use:

$ identify -list font | grep 'Font'

Text stroke

The size of the text stroke depends a little on the font, and what you like. 1-3 are good values. I usually go with 2, and sometimes (depending on the font) I use 1 or 3.

3 is probably closest to what you get at an online meme generator.

Example

Here's an example adding text 2 times (top and bottom).

$ magick in.jpg \
  -gravity north -font Impact \
  -pointsize 120 -fill white  \
  -stroke black -strokewidth 3 \
  -annotate +0+0 'Text at top' \
  out1.jpg
$ magick out1.jpg \
  -gravity south -font Impact \
  -pointsize 120 -fill white \
  -stroke black -strokewidth 3 \
  -annotate +0+0 'Text at bottom' \
  out2.jpg

It's more fun to spend time in Terminal, than at some online meme generator page. Plus, if you dig deeper into ImageMagick - you can add a lot of other effects as well. This was just a simple example.

// Happy hacking… 👍

· Eric

RPM: dynamic macro for %_topdir

Eric F 🇺🇦 — Tue, 31 Jan 2023 15:27:39 +0000

When building RPM packages with rpmbuild and you run rpmdev-setuptree to setup the build environment. The default macro for %_topdir is %{getenv:HOME}/rpmbuild.

If you don't want to use the default location, you can define that with --define on the command line, or define the macro in ~/.rpmmacros.

To use a custom path I've seen suggestions to use $(pwd) - which is a great way to select current path. However… If you then run rpmdev-setuptree in your home folder, forgetting about the macro. All folders end up all over your home folder.

So, here's an example to set a macro in ~/.rpmmacros to make it more dynamic - and to prevent your custom macro to run in HOME.

# RPM build
# ------------------------------------------
# rpmdev-setuptree:
#   - If run in HOME: use standard folder layout
#     Ex: HOME/rpmbuild
#   - if not: use PWD from current dir
#     Ex1: PWD/rpmbuild,
#     Ex2: $ mkdir project && cd rpmbuild/project
#          $ rpmdev-setuptree
#          HOME/rpmbuild/project/{SOURCES,SPECS,etc}
#
# This is mainly a protection, to prevent PWD to create
# the folders directly in HOME
#
%_topdir %([[ %(pwd) == %{getenv:HOME} ]] && \
    echo %{getenv:HOME}/rpmbuild || echo %(pwd))

So, now I can use it in better and more organized way. I put all in .rpm/rpmbuild/, and all projects can live side-by-side in there.

# Example
$ cd .rpm/rpmbuild/
$ mkdir baz && cd baz
$ rpmdev-setuptree
$ mkdir X_NOTES && touch X_NOTES/__notes.txt
$ cd ..
$ ls
foo bar baz

This setup works really great for me. The xtra X_NOTES folder is just something I find useful to keep notes in, backups, original files, logs from failed builds, etc. Whatever you dont want to put in the other folders. Keeping it a bit cleaner.

Hope you found it useful.

// Happy hacking… 👍

· Eric

One of the real gems with the DNF package manager: aliases

Eric F 🇺🇦 — Wed, 25 Jan 2023 20:57:22 +0000

One of the things i really like about the DNF package manager, is th built-in “alias” system. It's awesome. Because you know how it is, when you have package manager, and a lot of commands to keep track of - we tend to setup a bunch of aliases in our .bash_files. Like I have a few different ones I then source into my .bashrc depending on what system I've setup. So, on an Arch system, I have an pacman-file with only aliases for different pacman commands. With Debian I haven a file called ”apt”.
Then I can source them in .bashrc like:

for f in aliases functions git pacman; do
    [ -f ~/.bash.d/${f} ] && . ~/.bash.d/${f};
done

With DNF, there is no need for that. Well, except maybe 1. I do have an alias with: alias sdnf='sudo dnf '.

But, it's really great, and you can keep your .bash_files cleaner - and, when exploring what you can do and setup with the alias system - you'll learn a lot about your package manager.

So, DNF have (by default) already a bunch of pre-defined aliases. Like: in (install), rm (remove), ls (list), se (search), up (upgrade) + more. If you read the man dnf, you can see all the ones that are already made.

And it's really easy to add them your self. Here's how you do it:

# Basic syntax
$ sudo dnf alias add <alias>=<command/replacement>

# List your added aliases
$ dnf alias list

Examples

Here are a some examples, to show a few.

In Apt you have “show”, and in DNF it is “info”. So, after using a Debian system during the day, and then later back at home - I sometimes tend to mix them up. Easy to fix:

$ sudo dnf alias add show=info

There's already “up” for upgrade, so I've added:

$ sudo dnf alias add chup=check-update

There's already “rm” for remove, so I've added:

$ sudo dnf alias add aurm=autoremove

And here's an example of how you list them:

$ dnf alias list
Alias show='info'
Alias aurm='autoremove'
Alias chup='check-update'
Alias h='help'
Alias i='info'
Alias yin='in -y'
Alias yup='up -y'

There is one thing to be aware of though… You can read more about it in the manual, but when using an already defined command/alias - you need to “\backslash” it to prevent an infinite loop.

Maybe not a good example, but like:

$ sudo dnf alias add list='list installed'

That one needs a backslash, like:

$ sudo dnf alias add list='\list installed'

Well, it's easy, fun, and really useful, and less clutter in you .bash_files. Plus, you'll learn more about DNF when exploring all its options.

// Happy hacking… ⌨️ 👍

· Eric

Encrypting files with #Vim

Eric F 🇺🇦 — Thu, 19 Jan 2023 05:11:33 +0000

One of the easiest way to encrypt a file, is to use Vim. Here are two ways on how to set it up, and use it.

Setup

First, it could be good to check if your version actually is built with crypt support:

$ vim --version | grep +crypt
+cryptv            +lispindent        +quickfix          +wildmenu

And then you can check if there's a default value set with:

:set cm?

There are 3 cryptmethods:

VimCrypt~01: zip,
VimCrypt~02: blowfish,
VimCrypt~03: blowfish2.

You should use blowfish2, which is the strongest one.

So, to setup Vim for encryption, all you need is to set the cryptmethod (cm). In your .vimrc, you add:

" cryptmethod
set cm=blowfish2

To use it… Just pass the -x option when creating the file. You'll be asked to enter a password, twice - and then you're in.

$ vim -x <file>

Using a separate file

To take it another step, you can use a separate file to work with. In that way you can keep your normal settings in .vimrc - which may include all kinds of viminfo, swap files, backups, etc.

That's maybe not what you want when working with encrypted files. So, to keep the tracks down - create a new file: ~/.vim/vimencrypt, and then add this to the file:

"
" ~/.vim/vimencrypt
"
"
" Usage:
"   $ vim -u ~/.vim/vimencrypt -x <file>
"
" Or add an alias:
"   alias vimx='vim -u ~/.vim/vimencrypt -x '
"
"   $ vimx <file>
"

source ~/.vim/vimrc

set cm=blowfish2

set viminfo=
set nobackup
set noswapfile
set nowritebackup

You may need to adjust the path to where your .vimrc file is.

In that way you encrypt your files without using: viminfo, no backup file, no swap, etc. And it sources your standard .vimrc, so you will have your normal environment.

Usage:

$ vim -u ~/.vim/vimencrypt -x <file>

If you don't like the xtra typing… Add an alias:

alias vimx='vim -u ~/.vim/vimencrypt -x '

# and use it with:
$ vimx <file>

# Example
$ vimx testfile.txt

#  Result
$ cat testfile.txt
VimCrypt~03!���4����k
����u"E>*�1�~vh���ΊIA(7��@Y�Qj�9l��O

To read more about it, use the help:

:h cm

" or if you want it in a seaparate tab
:tab h cm

// Happy hacking… 👍

· Eric

Adding a swapfile in #Linux

Eric F 🇺🇦 — Fri, 13 Jan 2023 06:43:53 +0000

I usually go with a swapfile instead of a swap partition. So, during installation I don't create that partition, and instead I add the swapfile later.

So, here's how I do it.

First, I do everything as su:

~$ su -
Password:
~#

Create the directory and the swapfile. I prefer the path /var/vm/. Others may prefer /var/swap/. To create the swapfile - you can use dd, or fallocate if you prefer that one. I use dd.

The size of the swapfile may vary on your needs. I usually go with quite a big one, so in case I want to hibernate - there will be enough room. So, on an old laptop with 3G of RAM - I'll go with 4G.

~# mkdir /var/vm && cd /var/vm
vm# dd if=/dev/zero of=./swapfile0 bs=1M count=4096 status=progress 
4237295616 bytes (4,2 GB, 3,9 GiB) copied, 45 s, 94,2 MB/s
4096+0 records in
4096+0 records out
4294967296 bytes (4,3 GB, 4,0 GiB) copied, 45,6187 s, 94,1 MB/s

And set the permissions to 600:

vm# chmod 600 swapfile0
vm# ls -l swapfile0
total 4194304
-rw-------. 1 root root 4294967296  5 jan 03.14 swapfile0

Then make it an actual swapfile, turn the swap on, and check the status.

vm# mkswap swapfile0
Setting up swapspace version 1, size = 4 GiB (4294963200 bytes)
no label, UUID=<unique hash string>
vm# swapon swapfile0
vm# swapon -s
Filename            Type        Size    Used    Priority
/var/vm/swapfile0   file        4194300 0       -2

To make it mount on boot, we need to add it to /etc/fstab. So, with your favorite editor (eg. vim, vi, nano, etc)…

vm# vim /etc/fstab

And add these lines to the end of the file:

# Swapfile0
/var/vm/swapfile0   none    swap    defaults    0 0

Using the free command will get you information on how much swap you have and are using.

$ free -h
              total        used        free      shared  buff/cache   available
Mem:          2,9Gi       1,3Gi       493Mi       140Mi       1,1Gi       1,3Gi
Swap:         4,0Gi       132Mi       3,9Gi

SELinux

To make sure it works fine with SELinux, we need to set the correct context to the file: 'swap_t'.

~# semanage fcontext -a -t swapfile_t '/var/vm/swapfile0'
~# restorecon /var/vm/swapfile0 
~# ls -lZ /var/vm/
total 4194304
-rw-------. 1 root root unconfined_u:object_r:swapfile_t:s0 4294967296  5 jan 03.17 swapfile0

Tuning

To tune the cache so it doesn't swap too much, you can add these settings to sysctl.conf. In some systems/distros, you can add them directly there. In others you make an xtra file that will be sourced.

On my Rocky Linux system, I use an xtra file, like this:

~# vim /etc/sysctl.d/90-swappiness.conf

Then add this content:

#
# /etc/sysctl.d/90-swappiness.conf
#
# Description:
#     sysctl.conf settings for swap
#

vm.swappiness=10
vm.vfs_cache_pressure=40

vm.dirty_background_ratio=10
vm.dirty_ratio=15

Now all is good. :)

// Happy hacking… 👍

· Eric

Stop Chromium from asking about default browser

Eric F 🇺🇦 — Sun, 08 Jan 2023 22:35:59 +0000

I have to admit, I'm not a huge Chrom* fan - but still need it from time to time. So, I have it installed. It comes with a few annoyances though… One is it keeps asking about not being the default browser. I use Firefox, of course. :) So, here's a quick-tip on how to disable that.

After searching around a little bit and found the great startup parameter -no-default-browser-check. So, to use it… Let's not mess with the original file. It might be overwritten on any update.

Copy the original file into ~/.local/ instead.

cd ~/.local/share/applications
cp /usr/share/applications/chromium-browser.desktop .

Now you can open the file in your favorite editor, and then there are 3 places to edit.

I also cut out all the optional translation lines - just keeping the default and swedish. So, the file looks like this after my edits:

[Desktop Entry]
Version=1.0
Name=Chromium
Comment=Access the Internet
Comment[sv]=Surfa på Internet
GenericName=Web Browser
GenericName[sv]=Webbläsare
Exec=/usr/bin/chromium-browser -no-default-browser-check %U
Terminal=false
X-MultipleArgs=false
Type=Application
Icon=chromium-browser
Categories=Network;WebBrowser;
MimeType=application/pdf;application/rdf+xml;application/rss+xml;application/xhtml+xml;application/xhtml_xml;application/xml;image/gif;image/jpeg;image/png;image/webp;text/html;text/xml;x-scheme-handler/http;x-scheme-handler/https;
StartupWMClass=Chromium-browser
Keywords=web;browser;internet;
Actions=new-window;new-private-window;

X-Desktop-File-Install-Version=0.23

[Desktop Action new-window]
Name=Open a New Window
Name[en-US]=New Window
Name[sv-SE]=Nytt fönster
Exec=chromium-browser -no-default-browser-check %U

[Desktop Action new-private-window]
Name=Open a New Private Window
Name[en-US]=New Private Window
Name[sv-SE]=Nytt privat fönster
Exec=chromium-browser -no-default-browser-check --incognito %U

Now, you can also checkout this great post by @rahedmir on “How to Fix Google Chrome/Chromium asks for password to unlock keyring in Linux”, to make it stop asking about the keyring.

If you want that one to? Edit your changes above, and use them together as:

-no-default-browser-check --password-store=basic

No more bugging about not being the default browser. 🤞 Hope you found it useful.👍

· Eric

Bash: clearing the scrollback

Eric F 🇺🇦 — Sat, 07 Jan 2023 09:47:11 +0000

So, clearing the screen in Terminal may be the most trivial thing to do - you type clear or use the keyboard shortcut Ctrl-L. And then of course you can/will setup some alias to make it easier.

But, I wanted to do a better setup, to also clear the scrollback. Basically when you type clear, it'll only push it out of screen, leaving you with a blank screen - but you can still scroll back to the previous output.

Now, there are several ways to do that, and everyone has their own way and habits. This is what I use.

First, there are some distros and other OS's that already do this by default. OS X/macOS will clear the scrollback with its keyboard shortcut, and Debian had that already fixed with their Ctrl-L. But, not all have that - and just the screen command definitely doesn't clear it.

Aliases

First you can always have a few handy aliases, like c & k.

alias c='clear'
alias k="printf '\\033c'"

The alias k will clear the scrollback.

Keyboard shortcut

If your keyboard shortcut doesn't clear the scrollback you can map it with a bind (readline) command. I've seen serveral examples using that. But, one caveat is that whatever command you put in that bind line - it'll end up in the history. So, we have to be creative. :)

Bash have 2 different commands to clear the screen: clear-display (M-C-l) and clear-screen (C-l) (see Ref manual). The shortcut Ctrl-L uses clear-screen.

I was looking through the list of builtins in my Bash version, and it didn't have clear-display. Maybe it's gone, because normally - using Ctrl-Alt-L is the shortcut to lock the (computer) screen, and you'll need to login again. But, that's the command we want.

So, here's the code. You can use this in your .bashrc or /etc/bashrc (or where you want to keep your Bash stuff):

# Mimic readline's "clear-display (M-C-l)" behaviour,
# and bind it to C-l (ie. replacing: "clear-screen (C-l)")
function clear-display() {
    printf "\\033c" && history -d $(history 1);
}

bind '"\C-l": "\C-e\C-uclear-display\C-m\C-y"'

Ok, so what the code does. It will bind Ctrl-L (\C-l) to first go to the end of the line (\C-e) and cut it to the beginning of the line (\C-u). Then run the function clear-display(), make a new line (\C-m), and then paste in what was cut out (\C-y).

When I was looking at other examples, they used \C-a\C-k - which is the opposite way. Go to the beginning and cut it from there. I found that way didn't work when pasting it back.

Since everything run by bind will end up in Bash's history… we add history -d $(history 1) to clear it out.

Well, that's it.

This is maybe a bit overkill, but “old habits” and “muscle memory” are two difficult things to escape. ^_^

// Happy Hacking…

· Eric

A few notes…

Eric F 🇺🇦 — Sat, 31 Dec 2022 03:39:55 +0000

$ systemctl enable efdev --now

So, I guess some kind of intro post could nice and useful. I actually have (had) a blog I could write on, but… I hit a few road bumps a couple of years ago, including my computer broke down, plus a lot of other s****y things (I won't go into here). And my computer broke down in the middle of switching blog tools. I was going to move from Octopress to Pelican. Hopefully, in a couple of three months or so, I'll be able to fix all that again.

Meanwhile… Still need a place to express myself, or write stuff I need to post of share. Been looking at “dev.to” for a long time, and it seems like a great place to be, and to write som stuff at.

I guess when my site/blog is up and running again - I'll use this space to write shorter stuff. Like quick-tips, short notes, &/or maybe as compliment to a tweet. I don't know. We'll see.

Since it's the last day of the year…

“Happy New 2023” to you all.🎆🥂 Let's hope next year will be a good one.🤞👍

· Eric