Bash

Learning resources

Official documentation

• Bash Reference Manual

• Bash FAQ

• Debian manpage for Bash

• man -a intro

Misc

• http://mywiki.wooledge.org/

• http://mywiki.wooledge.org/BashGuide

• http://mywiki.wooledge.org/BashSheet

• http://mywiki.wooledge.org/BashPitfalls

• http://wiki.bash-hackers.org/start

• Google Shell Style Guide

• Introduction to Advanced Usage of GNU Bash

Tools

• Shellcheck : lint tool for shell scripts

• BATS : Bash Unit Testing with Bash Automated Testing System

Pitfalls

Quoting in Bash

• Grymoire : Quote

• https://stackoverflow.com/questions/6697753/difference-between-single-and-double-quotes-in-bash

• http://madhukaudantha.blogspot.com/2016/07/grep-quotes-in-linux.html

• https://superuser.com/questions/731105/why-doesnt-grep-work-with-single-quotes

• https://serverfault.com/questions/69283/when-to-use-single-quote-double-quote-in-grep

• https://askubuntu.com/questions/432064/using-grep-to-search-texts-with-single-quote

• http://www.gnu.org/software/bash/manual/bashref.html#Single-Quotes

Globbing in Bash

Filename expansion is called "globbing"

Unary operator expected

• https://askubuntu.com/questions/914842/eq-unary-operator-expected

A unary operator only has one argument. A binary operator has two arguments.

For example, -eq is a binary operator, because it has two arguments and figures out whether they're equal.

When the shell sees [ 3 -eq 3 ], everything is fine, because -eq takes two arguments, and it has been given two arguments, the 3s. What if one of those was blank, though? It would be either [ -eq 3 ] or [ 3 -eq ]. Those are missing one of the arguments, so the shell gets to thinking you meant to use an operator that only has one argument, a unary operator.

Your variables can be blank, causing just this problem. To avoid the issue, surround all uses of a variable with double quotes.

Solutions to common problems

Building my own library with my user-defined functions

• Build your own Bash functions library

Handling command line arguments

• Handling command line arguments in Bash

Using colors in Bash

• https://misc.flogisoft.com/bash/tip_colors_and_formatting

• https://www.shellhacks.com/bash-colors/

Strings manipulation

• https://www.tldp.org/LDP/abs/html/string-manipulation.html

• https://www.cyberciti.biz/faq/how-to-extract-substring-in-bash/

• https://stackabuse.com/substrings-in-bash/

• https://www.thegeekstuff.com/2010/07/bash-string-manipulation/

• Uppercase and lowercase for strings

Snippets

• Bash snippets

Bash cheatsheet

• Bash cheatsheet

Back to top

Index