Introduction
Hello fellow programmers 👋 In this article, I will shed the light on some useful/basic bash commands and tools that might help you save time while scripting. To make it easy to follow, the article will adhere to the following format:
- command
- description
- format
- examples
Commands
1. man
Description:
manis a useful command that displays the documentation/user manual to any command that you pass as an argument.Format
$ man [COMMAND]
- Example
Lets try to display the manual for the echo command:
$ man echo
the output of the previous line is:
ECHO(1) User Commands ECHO(1)
NAME
echo - display a line of text
SYNOPSIS
echo [SHORT-OPTION]... [STRING]...
echo LONG-OPTION
DESCRIPTION
Echo the STRING(s) to standard output.
-n do not output the trailing newline
-e enable interpretation of backslash escapes
-E disable interpretation of backslash escapes (default)
--help display this help and exit
--version
output version information and exit
...
Notice how the man command displays the output in a formatted manner. The output usually contains the name, description and the available options/flags for the given command.
Fun fact: you can use the man command to display the manual for the man command.
2. tldr
Description:
tldris a community driven tool that enhances the output of theman pagesand displays brief and meaningful examples for the given command. This tool is not available by default, so you will have to install it first. You can visit the tool's official page to easily add it to your environment.Format
$ tldr [COMMAND]
- Example
Lets try to display the tldr formatted docs for the echo command:
$ tldr echo
the output of the previous line is:
echo
Print given arguments.
Print a text message. Note: quotes are optional:
echo "{{Hello World}}"
Print a message with environment variables:
echo "{{My path is $PATH}}"
Print a message without the trailing newline:
echo -n "{{Hello World}}"
Append a message to the file:
echo "{{Hello World}}" >> {{file.txt}}
Enable interpretation of backslash escapes (special characters):
echo -e "{{Column 1\tColumn 2}}"
Note how it gives concise examples to illustrate the usage of the given command, unlike man.
Similar to man, you can use the tldr command to display the formatted docs for tldr.
3. cat
Description:
catis an awesome command that lets you display files in the standard output, concatenate files together or create new files.Format
$ cat [OPTION]... [FILE]...
- Example
Suppose that we want to print out the content of a file named example to the standard output. It can be done using:
$ cat example
If we want to append two files, named foo and bar respectively, and save the output in a file called output:
$ cat foo bar > output
To create a new file called new_file:
$ cat > new_file
who doesn't like cats?
4. grep
Description:
grepis a powerful tool that lets you match patterns (using regex) or exact strings in a given text. It prints out the lines that contain the given pattern/string.Format
$ grep [OPTION...] PATTERNS [FILE...]
- Example
Suppose that I have a python file called stock_analysis.py and it contains the following code:
import requests
import numpy as np
from matplotlib import pyplot as plt
eminem = requests.get("https://www.google.com/")
import pandas as pd
df = pd.read_csv('my_file.csv')
and I want to display all the imports included in that file. We can simply use:
$ grep -F "import" stock_analysis.py
the output of the previous command is:
import requests
import numpy as np
from matplotlib import pyplot as plt
import pandas as pd
Suppose that instead of displaying all the imports, We want to display the aliased imports only. We can use the grep command along with regex:
$ grep "import.*as.*" stock_analysis.py
the output of the previous command is:
import numpy as np
from matplotlib import pyplot as plt
import pandas as pd
5. curl
Description:
curlis a cli tool that lets you transfer data from/to a server over various protocols such as HTTP and FTP.curlis a massive tool that has lots of powerful features and is open source, so I encourage you to read more about it.Format
$ curl [OPTION...] [URL...]
- Example
Suppose that I want to retrieve a random dad joke from the icanhazdadjoke API using curl. I would send a GET request and specify that I want to only accept text/plain data in the header:
$ curl -X GET https://icanhazdadjoke.com/ -H "Accept: text/plain"
this was the joke that I've received:
Is the pool safe for diving? It deep ends.
this API is a lot of fun and I encourage you to try your luck with it!
6. | - pipes
Description:
|, or shall I say, pipes let you use the output of a program as an input to another program. A series of bash commands connected together using pipes is usually called a pipeline.Format
$ [COMMAND1] | [COMMAND2] | ...
- Example
Suppose that we want to retrieve all Eminem songs that contains the word "love". We would first use curl to retrieve the list of songs from the internet, then use the output from the request as an input to the grep command to search for exact matches of the word "love":
$ curl -X GET https://pastebin.com/raw/6nfK1QRb | grep -F -i "love"
the final filtered list of songs is:
14. Never Love Again$
14 M-bM-^@M-^T Love Game (feat. Kendrick Lamar)$
Rihanna M-bM-^@M-^S Love The Way You Lie Part II (feat. Eminem)$
09 M-bM-^@M-^S No Love (feat. Lil Wayne)$
15 M-bM-^@M-^S Love the Way You Lie (feat. Rihanna)$
17 M-bM-^@M-^S Crazy in Love$
02 M-bM-^@M-^S I Love You More$
03 M-bM-^@M-^S I Love You More (Original)$
02 M-bM-^@M-^S Love Me M-bM-^@M-^S Obie Trice, Eminem & 50 Cent$
Eminem M-bM-^@M-^S Thug Love (feat. 50 Cent & Beyonce) (Remix)$
7. ! - bang
Description:
!, or shall I say, bang is a useful command that lets you execute and play around with bash commands history. Combined with other characters and keywords, It can be extremely time efficient to use it instead of retyping commands from the bash history.Format
$ !! # execute the last executed command
$ !* # execute the last command except for the last argument
$ !$ # get the last argument of the last executed command
$ ![PATTERN] # execute the the first command that matches the given pattern from the bash history
8. head and tail
Description:
headandtailare two useful bash commands that lets you display a portion of a given file. The former is used to display the firstnlines of a file, and the latter is used to display the lastnlines of a file. By default,nis equal to10.Format
$ head [OPTION]... [FILE]...
$ tail [OPTION]... [FILE]...
- Example
Dump the first and last 20 lines of a file called main.js in a file called example:
$ head --lines=20 main.js > example
$ tail --lines=20 main.js >> example
9. fzf
Description:
fzfis an awesome cli tool for performing fuzzy search on your files or stdout through the command line. Honestly,fzfis a really powerful tool that can do alot, but in this article, we will focus on two main usages for this tool: searching for files and search for content from the stdout. You can read more aboutfzfthrough their github page.Format
$ fzf [OPTION]
- Example
By default, running the fzf command without any options will open an interactive searching session within the current directory. The following gif shows how we could fuzzy search for files in the current directory:
We can also pipe the stdout to fzf and search for content within the provided context:
Closing Remarks
Knowing your way around bash commands and tools can accelerate your productivity immensely. This article has covered some of the useful ones the I use on a daily basis. Feel free to mention your favorite bash commands/tools in the comments. Nevertheless, Have a great day🎉.
Top comments (1)
Thanks for this 😊