\documentclass[10pt,a4paper]{article}

% Packages
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\usepackage{multicol}           % Allows multicols in tables
\usepackage{tabularx}           % Intelligent column widths
\usepackage{tabulary}           % Used in header and footer
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%\usepackage[utf8x]{inputenc}    % For unicode character support
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\usepackage{colortbl}           % For coloured tables
\usepackage{setspace}           % For line height
\usepackage{lastpage}           % Needed for total page number
\usepackage{seqsplit}           % Splits long words.
%\usepackage{opensans}          % Can't make this work so far. Shame. Would be lovely.
\usepackage[normalem]{ulem}     % For underlining links
% Most of the following are not required for the majority
% of cheat sheets but are needed for some symbol support.
\usepackage{amsmath}            % Symbols
\usepackage{MnSymbol}           % Symbols
\usepackage{wasysym}            % Symbols
%\usepackage[english,german,french,spanish,italian]{babel}              % Languages

% Document Info
\author{eugvol}
\pdfinfo{
  /Title (bash-scripting.pdf)
  /Creator (Cheatography)
  /Author (eugvol)
  /Subject (Bash scripting Cheat Sheet)
}

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% Commands
\newcommand{\SetRowColor}[1]{\noalign{\gdef\RowColorName{#1}}\rowcolor{\RowColorName}} % Shortcut for row colour
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\newcommand{\tn}{\tabularnewline} % Required as custom column type in use

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% Header and Footer
\pagestyle{fancy}
\fancyhead{} % Set header to blank
\fancyfoot{} % Set footer to blank
\fancyhead[L]{
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{C}
    \SetRowColor{DarkBackground}
    \vspace{-7pt}
    {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent
        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
    }
\end{tabulary}
\columnbreak
\begin{tabulary}{11cm}{L}
    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Bash scripting Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{eugvol} via \textcolor{DarkBackground}{\uline{cheatography.com/198523/cs/42009/}}}
\end{tabulary}
\end{multicols}}

\fancyfoot[L]{ \footnotesize
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{LL}
  \SetRowColor{FootBackground}
  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}eugvol \\
  \uline{cheatography.com/eugvol} \\
  \end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Not Yet Published.\\
   Updated 16th January, 2024.\\
   Page {\thepage} of \pageref{LastPage}.
\end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Sponsor}}  \\
  \SetRowColor{white}
  \vspace{-5pt}
  %\includegraphics[width=48px,height=48px]{dave.jpeg}
  Measure your website readability!\\
  www.readability-score.com
\end{tabulary}
\end{multicols}}




\begin{document}
\raggedright
\raggedcolumns

% Set font size to small. Switch to any value
% from this page to resize cheat sheet text:
% www.emerson.emory.edu/services/latex/latex_169.html
\footnotesize % Small font.

\begin{multicols*}{2}

\begin{tabularx}{8.4cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Shebang}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{\#!/bin/bash} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\mymulticolumn{1}{x{8.4cm}}{\#!/usr/bin/env bash} \tn 
% Row Count 2 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{5.04 cm} x{2.96 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Variables}}  \tn
% Row 0
\SetRowColor{LightBackground}
`MY\_STR1=Hello` & Hello \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
`MY\_STR2=\$MY\_STR1` & Hello \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
`MY\_NUM=45` & 45 \tn 
% Row Count 3 (+ 1)
% Row 3
\SetRowColor{white}
`MY\_STR3="Num value is \$MY\_NUM"` & Num value is 45 \tn 
% Row Count 5 (+ 2)
% Row 4
\SetRowColor{LightBackground}
`MY\_STR4='Num value is \$MY\_NUM'` & Num value is \$MY\_NUM \tn 
% Row Count 7 (+ 2)
% Row 5
\SetRowColor{white}
`MY\_PATH=/etc` & /etc \tn 
% Row Count 8 (+ 1)
% Row 6
\SetRowColor{LightBackground}
`MY\_COMMAND=\$(ls \$MY\_PATH)` & result of {\bf{ls /etc}} \tn 
% Row Count 10 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{1.008 cm} x{2.736 cm} p{0.792 cm} x{2.664 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{4}{x{8.4cm}}{\bf\textcolor{white}{Globs}}  \tn
% Row 0
\SetRowColor{LightBackground}
* & Any number of characters inc. none & *.txt & test1.txt \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
? & Matches single character & ?.txt & a.txt, not ab.txt \tn 
% Row Count 5 (+ 2)
% Row 2
\SetRowColor{LightBackground}
{[}abc{]} & Matches any one of enclosed characters & {[}ab{]}.txt & a.txt, b.txt, not c.txt \tn 
% Row Count 8 (+ 3)
% Row 3
\SetRowColor{white}
{[}a-c{]} & Matches any character in the range & {[}a-c{]}.txt & a.txt, b.txt, c.txt, not d.txt \tn 
% Row Count 11 (+ 3)
% Row 4
\SetRowColor{LightBackground}
\seqsplit{?(pattern-list)} & Extended: matches zero or one occurrence of the given patterns & \seqsplit{?(a|b)}.txt & a.txt, b.txt, .txt \tn 
% Row Count 16 (+ 5)
% Row 5
\SetRowColor{white}
\seqsplit{*(pattern-list)} & Extended: matches zero or more occurrences of the given patterns & \seqsplit{*(a|b|c)}.txt & a.txt, aa.txt, abac.txt, .txt \tn 
% Row Count 21 (+ 5)
% Row 6
\SetRowColor{LightBackground}
\seqsplit{+(pattern-list)} & Extended: matches one or more occurrences of the given patterns & \seqsplit{+(a|b|c)}.txt & a.txt, ab.txt, ba.txt, aaabbbccc.txt, etc \tn 
% Row Count 26 (+ 5)
% Row 7
\SetRowColor{white}
\seqsplit{@(pattern-list)} & Extended: matches one of the given patterns & \seqsplit{@(a|b|c)}.txt & a.txt, b.txt, or c.txt \tn 
% Row Count 29 (+ 3)
% Row 8
\SetRowColor{LightBackground}
!(pattern-list) & Extended: matches anything except one of the given patterns & !(a|b|c).txt & any .txt files except a.txt, b.txt, c.txt \tn 
% Row Count 33 (+ 4)
\hhline{>{\arrayrulecolor{DarkBackground}}----}
\SetRowColor{LightBackground}
\mymulticolumn{4}{x{8.4cm}}{{\bf{shopt -s extglob}} turns on extended globs. \newline {\bf{shopt -s nullglob}} return no output if no matches, otherwise returns the glob pattern. \newline {\bf{shopt -s nocaseglob}} makes globing case-insensitive. \newline {\bf{shopt -s dotglob}} includes filenames starting with a dot (hidden files) in glob patterns.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}----}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{p{0.8 cm} x{7.2 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{File tests}}  \tn
% Row 0
\SetRowColor{LightBackground}
-d & returns 0 if directory \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
-f & returns 0 if file \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
-e & returns 0 if exists \tn 
% Row Count 3 (+ 1)
% Row 3
\SetRowColor{white}
-s & returns 0 if file isn't empty \tn 
% Row Count 4 (+ 1)
% Row 4
\SetRowColor{LightBackground}
-r & returns 0 if file exists and permissions are granted (-w, -x are also possible) \tn 
% Row Count 7 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{8.4cm}}{Use either {\bf{test -flag argument}} or {\bf{{[} -flag argument {]}}} format. \newline Use {\bf{echo \$?}} to get the result in bash cmd}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{4 cm} x{4 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{String tests}}  \tn
% Row 0
\SetRowColor{LightBackground}
`{[} \$a = "Hello" {]}` & returns 0 if strings are equal \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
`{[} \$a != \$b {]}` & returns 0 if strings are not equal \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
`{[} -z \$a {]}` & returns 0 if \$a length is zero \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
`{[} -n \$a {]}` & returns 0 if \$a length is non-zero \tn 
% Row Count 8 (+ 2)
% Row 4
\SetRowColor{LightBackground}
`{[}{[} \$a == \$b {]}{]}` & returns 0 if strings are equal \tn 
% Row Count 10 (+ 2)
% Row 5
\SetRowColor{white}
`{[}{[} \$a != \$b {]}{]}` & returns 0 if strings are not equal \tn 
% Row Count 12 (+ 2)
% Row 6
\SetRowColor{LightBackground}
`{[}{[} \$a \textgreater{} \$b {]}{]}` & returns 0 if \$a is alphabetically greater than \$b \tn 
% Row Count 15 (+ 3)
% Row 7
\SetRowColor{white}
`{[}{[} \$a \textless{} \$b {]}{]}` & returns 0 if \$a is alphabetically less than \$b \tn 
% Row Count 18 (+ 3)
% Row 8
\SetRowColor{LightBackground}
`{[}{[} "\$FILENAME" == *.txt {]}{]}` & returns 0 if \$FILENAME matches glob pattern \tn 
% Row Count 21 (+ 3)
% Row 9
\SetRowColor{white}
`{[}{[} "Hello !!" =\textasciitilde{} \textasciicircum{}Hello{[}{[}:space:{]}{]}.* {]}{]}` & returns 0 if string matches regex pattern \tn 
% Row Count 24 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{8.4cm}}{{\emph{White spaces}} are important.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{3.76 cm} x{4.24 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Integers test}}  \tn
% Row 0
\SetRowColor{LightBackground}
\{\{ac\}\}Within {[} {]} & \{\{ac\}\}Within {[}{[} {]}{]} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
-eq & == \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
-ne & != \tn 
% Row Count 3 (+ 1)
% Row 3
\SetRowColor{white}
-gt & \textgreater{} \tn 
% Row Count 4 (+ 1)
% Row 4
\SetRowColor{LightBackground}
-lt & \textless{} \tn 
% Row Count 5 (+ 1)
% Row 5
\SetRowColor{white}
-ge & \textgreater{}= \tn 
% Row Count 6 (+ 1)
% Row 6
\SetRowColor{LightBackground}
-le & \textless{}= \tn 
% Row Count 7 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Decimals comparison}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{decimal1=3.14 \newline decimal2=2.71 \newline  \newline \# Use bc to compare decimal numbers \newline result=\$(echo "\$decimal1 \textgreater{} \$decimal2" | bc -l) \newline  \newline if {[} "\$result" -eq 1 {]}; then \newline     echo "\$decimal1 is greater than \$decimal2" \newline elif {[} "\$result" -eq 0 {]}; then \newline     echo "\$decimal1 is equal to \$decimal2" \newline else \newline     echo "\$decimal1 is less than \$decimal2" \newline fi} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.48 cm} x{5.52 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Conditional structures}}  \tn
% Row 0
\SetRowColor{LightBackground}
cmd1 || cmd2 & run cmd1, if fails run cmd2 \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
cmd1 \&\& cmd2 & run cmd1, if ok run cmd2 \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{8.4cm}}{`if {[} \$a -gt 5 {]} \&\& {[} \$b -eq 20 {]}; then\{\{nl\}\}     echo "a \textgreater{} 5 AND b=20"\{\{nl\}\}elif {[} \$b -lt 15 {]} || {[} \$c -ge 30 {]}; then\{\{nl\}\}     echo "b\textless{}15 OR c\textgreater{}=30"\{\{nl\}\}elif ! {[} \$a -eq 10 {]}; then\{\{nl\}\}     echo "a!=10"\{\{nl\}\}else\{\{nl\}\}     echo "None of the conditions met"\{\{nl\}\}fi`} \tn 
% Row Count 8 (+ 6)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{8.4cm}}{`case \$input in\{\{nl\}\}     start|START)\{\{nl\}\}         echo "Starting the process..."\{\{nl\}\}         ;;\{\{nl\}\}     stop|STOP)\{\{nl\}\}         echo "Stopping the process..."\{\{nl\}\}         ;;\{\{nl\}\}     *)\{\{nl\}\}         echo "Invalid option: \$input"\{\{nl\}\}         ;;\{\{nl\}\} esac`} \tn 
% Row Count 14 (+ 6)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{8.4cm}}{`options=("START" "STOP")\{\{nl\}\}select opt in "\$options{[}@{]}"\{\{nl\}\}do\{\{nl\}\}    case \$opt in\{\{nl\}\}     START)\{\{nl\}\}         echo "Starting the process..."\{\{nl\}\}         ;;\{\{nl\}\}     STOP)\{\{nl\}\}         echo "Stopping the process..."\{\{nl\}\}         ;;\{\{nl\}\}     *)\{\{nl\}\}         echo "Invalid option: \$input"\{\{nl\}\}         ;;\{\{nl\}\} esac\{\{nl\}\}done`} \tn 
% Row Count 21 (+ 7)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{1.8 cm} x{1.8 cm} x{1.8 cm} x{1.8 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{4}{x{8.4cm}}{\bf\textcolor{white}{For loop}}  \tn
% Row 0
\SetRowColor{LightBackground}
Basic & C-style syntax & Over command output & Over array elements \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
`for i in 1 2 3 4 5\{\{nl\}\}do\{\{nl\}\}     echo "Number \$i"\{\{nl\}\}done` & `for ((i = 1; i \textless{}= 5; i++))\{\{nl\}\}do\{\{nl\}\}     echo "Number \$i"\{\{nl\}\}done` & `for user in \$(cat \seqsplit{/etc/passwd} | cut -d ':' -f 1)\{\{nl\}\}do\{\{nl\}\}     echo "User: \$user"\{\{nl\}\}done` & \seqsplit{`arr=("apple"} "banana" "cherry")\{\{nl\}\}for fruit in "\$\{arr{[}@{]}\}"\{\{nl\}\}do\{\{nl\}\}     echo "Fruit: \$fruit"\{\{nl\}\}done` \tn 
% Row Count 14 (+ 12)
% Row 2
\SetRowColor{LightBackground}
Over files & Over range with break & Over range with step & Over string \tn 
% Row Count 17 (+ 3)
% Row 3
\SetRowColor{white}
`for file in /path/to/directory/*\{\{nl\}\}do\{\{nl\}\}     echo \seqsplit{"Processing} \$file"\{\{nl\}\}done` & `for i in \{1..10\}\{\{nl\}\}do\{\{nl\}\}     if {[} "\$i" -eq 5 {]}; then\{\{nl\}\}         break\{\{nl\}\}     fi\{\{nl\}\}     echo "Number \$i"\{\{nl\}\}done` & `for i in \{0..10..2\}\{\{nl\}\}do\{\{nl\}\}     echo "Number \$i"\{\{nl\}\}done` & `string="hello"\{\{nl\}\}for char in \$(echo \$string | fold -w1)\{\{nl\}\}do\{\{nl\}\}     echo \seqsplit{"Character:} \$char"\{\{nl\}\}done` \tn 
% Row Count 30 (+ 13)
\hhline{>{\arrayrulecolor{DarkBackground}}----}
\SetRowColor{LightBackground}
\mymulticolumn{4}{x{8.4cm}}{{\bf{break}} and {\bf{continue}} can be used}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}----}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{p{0.72 cm} x{2.808 cm} p{0.72 cm} x{2.952 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{4}{x{8.4cm}}{\bf\textcolor{white}{Special characters and variables}}  \tn
% Row 0
\SetRowColor{LightBackground}
/ & Root directory & \$HOME & The current user's home directory \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
. & Current directory & \$PWD & The current working directory \tn 
% Row Count 5 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\textasciitilde{} & Current user directory & \$PATH & A list of directories separated by colons (:) where the system looks for executable files \tn 
% Row Count 11 (+ 6)
% Row 3
\SetRowColor{white}
\textasciitilde{}username & Directory of a user with username & \$USER & The username of the user running the script \tn 
% Row Count 14 (+ 3)
% Row 4
\SetRowColor{LightBackground}
.. & Parent directory & \seqsplit{\$HOSTNAME} & The hostname of the machine the script is running on \tn 
% Row Count 18 (+ 4)
% Row 5
\SetRowColor{white}
\$0 & The name of the Bash script & \seqsplit{\$RANDOM} & Returns a different random number each time is it referred to \tn 
% Row Count 22 (+ 4)
% Row 6
\SetRowColor{LightBackground}
\$1-\$9 & The first 9 arguments to the Bash script & \seqsplit{\$SECONDS} & Number of seconds since the shell was started. Can be used to measure elapsed time of a script \tn 
% Row Count 28 (+ 6)
% Row 7
\SetRowColor{white}
\$\# & Number of arguments passed to Bash script & \seqsplit{\$OLDPWD} & Previous directory \tn 
% Row Count 31 (+ 3)
\end{tabularx}
\par\addvspace{1.3em}

\vfill
\columnbreak
\begin{tabularx}{8.4cm}{p{0.72 cm} x{2.808 cm} p{0.72 cm} x{2.952 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{4}{x{8.4cm}}{\bf\textcolor{white}{Special characters and variables (cont)}}  \tn
% Row 8
\SetRowColor{LightBackground}
\$@ & All the arguments supplied to the Bash script & \seqsplit{\$LINENO} & Current line number in a script or shell. Used for debugging \tn 
% Row Count 4 (+ 4)
% Row 9
\SetRowColor{white}
\$? & The exit status of the most recently run process & \seqsplit{\$SHELL} & Path to the user's default shell \tn 
% Row Count 8 (+ 4)
% Row 10
\SetRowColor{LightBackground}
\$\$ & The process ID of the current script & \$UID & User unique ID \tn 
% Row Count 11 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}----}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{3.52 cm} x{4.48 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Associative arrays}}  \tn
% Row 0
\SetRowColor{LightBackground}
Declare an associative array & `declare -A fruits` \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
Adding/appending an item & `fruits{[}apple{]}="red"\{\{nl\}\}fruits{[}banana{]}="yellow"` \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
Reading an item & `echo "The apple is \$\{fruits{[}apple{]}\}"` \tn 
% Row Count 7 (+ 2)
% Row 3
\SetRowColor{white}
Changing an item value & `fruits{[}apple{]}="green"` \tn 
% Row Count 9 (+ 2)
% Row 4
\SetRowColor{LightBackground}
Removing an item & `unset fruits{[}banana{]}` \tn 
% Row Count 10 (+ 1)
% Row 5
\SetRowColor{white}
Looping through keys & `for key in "\$\{!fruits{[}@{]}\}"; do\{\{nl\}\}     echo "\$key"\{\{nl\}\}done` \tn 
% Row Count 13 (+ 3)
% Row 6
\SetRowColor{LightBackground}
Looping through values & `for value in "\$\{fruits{[}@{]}\}"; do\{\{nl\}\}     echo "\$value"\{\{nl\}\}done` \tn 
% Row Count 17 (+ 4)
% Row 7
\SetRowColor{white}
Looping through keys and values & `for key in "\$\{!fruits{[}@{]}\}"; do\{\{nl\}\}     echo "\$key: \$\{fruits{[}\$key{]}\}"\{\{nl\}\}done` \tn 
% Row Count 21 (+ 4)
% Row 8
\SetRowColor{LightBackground}
Length of an associative array & `echo \$\{\#fruits{[}@{]}\}` \tn 
% Row Count 23 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.128 cm} x{3.116 cm} x{2.356 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{3}{x{8.4cm}}{\bf\textcolor{white}{Arithmetics}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{3}{x{8.4cm}}{{\bf{let}} writes the result to a variable but doesn't print it. Used {\emph{only for integers}}.} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
`let b=2+5` & `let b=2*5` & `let c=\$a/\$b` \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
`let \seqsplit{c=\$a\%\$b`} & `let c=\$a**\$b` & `let "a = 5 + 2"` \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
`let "a=5+2"` & `let "c = \$a * \$b"` & `let "c = (2 + 3) * 4"` \tn 
% Row Count 8 (+ 2)
% Row 4
\SetRowColor{LightBackground}
`let a++` & `let b-{}-` & `let c+=1` \tn 
% Row Count 9 (+ 1)
% Row 5
\SetRowColor{white}
\mymulticolumn{3}{x{8.4cm}}{{\bf{expr}} returns the result and prints it. {\emph{Spaces}} are important. Used {\emph{only for integers}}.} \tn 
% Row Count 11 (+ 2)
% Row 6
\SetRowColor{LightBackground}
`expr 10 + 5` & `expr 3 * 2` & `expr 10 / 2` \tn 
% Row Count 13 (+ 2)
% Row 7
\SetRowColor{white}
`expr \$a - \$b` & `expr 11 \% 5` & `a=\$(expr 11 \% 5)` \tn 
% Row Count 15 (+ 2)
% Row 8
\SetRowColor{LightBackground}
\mymulticolumn{3}{x{8.4cm}}{{\bf{\$(())}} can also be used for arithmetics {\emph{with integers only}}.} \tn 
% Row Count 17 (+ 2)
% Row 9
\SetRowColor{white}
\seqsplit{`a=\$((3+4))`} & `b=\$((\$a-\$b))` & \seqsplit{`c=\$((a*b))`} \tn 
% Row Count 19 (+ 2)
% Row 10
\SetRowColor{LightBackground}
\seqsplit{`((b=++a))`} & `((b=-{}-a))` & \seqsplit{`c=\$((b+=3))`} \tn 
% Row Count 21 (+ 2)
% Row 11
\SetRowColor{white}
\mymulticolumn{3}{x{8.4cm}}{{\bf{bc}} is used for more complex calculations. It can deal {\emph{with decimals as well}}.} \tn 
% Row Count 23 (+ 2)
% Row 12
\SetRowColor{LightBackground}
`a=\$(echo "5 + 3" | bc)` & `b=\$(echo "10.5-2.3" | bc -l)` & `c=\$(echo "sqrt(25)" | bc -l)` \tn 
% Row Count 26 (+ 3)
% Row 13
\SetRowColor{white}
`d=\$(echo "2 \textasciicircum{} 3" | bc -l)` & \seqsplit{`rounded\_value=\$(echo} "scale=2; 10/3" | bc)` &  \tn 
% Row Count 29 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}---}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{4 cm} x{4 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{While/Until loops}}  \tn
% Row 0
\SetRowColor{LightBackground}
While & Until \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
`counter=1\{\{nl\}\}while {[} \$counter -le 10 {]}\{\{nl\}\}do\{\{nl\}\}    echo \$counter\{\{nl\}\}    ((counter++))\{\{nl\}\}done` & `counter=1\{\{nl\}\}until {[} \$counter -gt 10 {]}\{\{nl\}\}do\{\{nl\}\}    echo \$counter\{\{nl\}\}    ((counter++))\{\{nl\}\}done` \tn 
% Row Count 7 (+ 6)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{8.4cm}}{While with reading from a file} \tn 
% Row Count 8 (+ 1)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{8.4cm}}{`while IFS= read -r line; do\{\{nl\}\}     echo "\$line"\{\{nl\}\}done \textless{} filename.txt`} \tn 
% Row Count 10 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{4 cm} x{4 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Exporting env variables}}  \tn
% Row 0
\SetRowColor{LightBackground}
printenv & Print list of all env variables \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
export VAR="Hello World" & Create env variable (for current session only) \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
echo 'export NEW\_VAR="Hello World"' \textgreater{}\textgreater{} \textasciitilde{}/.bashrc & Create env variable for future sessions \tn 
% Row Count 8 (+ 3)
% Row 3
\SetRowColor{white}
source \textasciitilde{}/.bashrc & Reload the shell startup file (required after changing the file with prev. command) \tn 
% Row Count 13 (+ 5)
% Row 4
\SetRowColor{LightBackground}
export \seqsplit{PATH=\$PATH:newvalue} & Appending a value (for current session only) \tn 
% Row Count 16 (+ 3)
% Row 5
\SetRowColor{white}
unset VAR & Remove env variable \tn 
% Row Count 17 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{3.04 cm} x{4.96 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Arrays}}  \tn
% Row 0
\SetRowColor{LightBackground}
Explicit declaration & `declare -a my\_array` \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
Implicit creation & `my\_array=(element1 element2 element3)` \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
Read a single element & `echo \$\{my\_array{[}0{]}\}` \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
Read all elements & `echo \$\{my\_array{[}@{]}\}` \tn 
% Row Count 8 (+ 2)
% Row 4
\SetRowColor{LightBackground}
Changing an element & `my\_array{[}1{]}=new\_element` \tn 
% Row Count 10 (+ 2)
% Row 5
\SetRowColor{white}
Appending an element & `my\_array+=(element4)` \tn 
% Row Count 12 (+ 2)
% Row 6
\SetRowColor{LightBackground}
Removing an element & `unset my\_array{[}1{]}` \tn 
% Row Count 14 (+ 2)
% Row 7
\SetRowColor{white}
Length of an array & `echo \$\{\#my\_array{[}@{]}\}` \tn 
% Row Count 16 (+ 2)
% Row 8
\SetRowColor{LightBackground}
Looping through an array & `for element in "\$\{my\_array{[}@{]}\}"; do\{\{nl\}\}    echo \$element\{\{nl\}\}done` \tn 
% Row Count 19 (+ 3)
% Row 9
\SetRowColor{white}
Sparce array & `declare -a sparse\_array\{\{nl\}\}sparse\_array{[}3{]}="Third Element"\{\{nl\}\}sparse\_array{[}7{]}="Seventh Element"\{\{nl\}\}for index in "\$\{!sparse\_array{[}@{]}\}"; do\{\{nl\}\}    echo "Index \$index: \$\{sparse\_array{[}\$index{]}\}"\{\{nl\}\}done` \tn 
% Row Count 28 (+ 9)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{4 cm} x{4 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{ECHO and READ}}  \tn
% Row 0
\SetRowColor{LightBackground}
`echo "Hello, World!"` & Hello, World! \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
`echo -n "This is a "\{\{nl\}\}echo "single line."` & This is a single line. \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
`echo -e "This is a\textbackslash{}ttab\textbackslash{}tseparated\textbackslash{}ttext."` & This is a    tab    separated    text. \tn 
% Row Count 8 (+ 3)
% Row 3
\SetRowColor{white}
`echo -E "This is a\textbackslash{}ttab\textbackslash{}tseparated\textbackslash{}ttext."` & This is a\textbackslash{}ttab\textbackslash{}tseparated\textbackslash{}ttext. \tn 
% Row Count 11 (+ 3)
% Row 4
\SetRowColor{LightBackground}
`read var` & reading into a variable \tn 
% Row Count 13 (+ 2)
% Row 5
\SetRowColor{white}
`read var1 var2 var3` & reading into several variables \tn 
% Row Count 15 (+ 2)
% Row 6
\SetRowColor{LightBackground}
`read -a fruits` & reading into array (whitespace is the default delimiter) \tn 
% Row Count 18 (+ 3)
% Row 7
\SetRowColor{white}
`read -p "Enter your name: " name` & reading with prompt \tn 
% Row Count 20 (+ 2)
% Row 8
\SetRowColor{LightBackground}
`read -sp "Password: " password` & reading with silent input and prompt \tn 
% Row Count 22 (+ 2)
% Row 9
\SetRowColor{white}
`read -n 3 val` & reading with a limited number of characters \tn 
% Row Count 25 (+ 3)
% Row 10
\SetRowColor{LightBackground}
`read -t 5 val` & reading with 5s timeout \tn 
% Row Count 27 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}


% That's all folks
\end{multicols*}

\end{document}