Bash Cheatsheet

Special Arguments

Argument	Explanation
$#	Number of arguments
$*	All arguments
$@	All arguments, starting from first
$1	First argument
$_	Last argument of previous command

Character	Explanation
" "	Whitespace
$var, ${var}	Variable expansion
$(cmd)	Command substitution, returns command output
$((expression))	Arithmetic expansion
''	Literal string, special chars are ignored
""	String, special chars are evaluated
\	Escape special chars
#	Comment
=	Variable Assignment
[[ ]]	Evaluate conditional expression
!	Negate test or exit status
>, >>, <	Redirection
\|	Pipe output to another command
;	Command separator
{ }	Inline group, commands inside are treated as one command
( )	Subshell group, commands are executed in a new process
(( ))	Arithmetic expression, returns result
*, ?	Globs, wildcard matches
~	Home directory
&	Background command

Loop

Multi-Line

One-Liner

For

for i in list; do
    cmd
done

for i in list; do cmd; done

If-Else

if [ condition ]; do
    cmd
elif [condition ]; do
    cmd
else cmd
fi

if [ condition ]; do cmd; else cmd; fi

While

while [ condition ]; do
    cmd
done

while [ condition ]; do cmd; done

Command	Explanation	Usage
Sed	Stream Editor - transform text	sed -i "s/to replace/replacement/g"
Cut	Cut fields using delimiter	cut -d "<delimiter>" -f "<field # to cut>"