Bash cheatsheet

Arrays

read -a my_var

Reads list of strings from stdin to array my_var variable

mapfile -t my_var < file.txt

Read lines from the standard input into an indexed array variable

${a[@]}

Every array item

${a[@]:2}

Skip first two elements of array (slicing)

${#a}

Number of array items

readarray -d "," -t a <<< $input

Splits string in $input by "," delimiter and stores it in "a" variable

ls | readarray a

Reads command output into array "a"

Cursor movement

\e[1;1H

Moves cursor to 1:1 coordinates (absolutely)

\e[1A

Moves cursor 1 line up (above) (relatively)

\e[1B

Moves cursor 1 line down (bellow) (relatively)

\e[1C

Moves cursor 1 column right (relatively)

\e[1D

Moves cursor 1 column left (relatively)

String operations

${#string}

Extract substring from $string at $position

${string:position:length}

Extract $length characters substring from $string at $position (0-based)

${string/substring/replacement}

Replace first match of $substring with $replacement

${string//substring/replacement}

Replace all matches of $substring with $replacement

${string/#substring/replacement}

If $substring matches front end of $string, substitute $replacement for $substring

${string/%substring/replacement}

If $substring matches back end of $string, substitute $replacement for $substring

PS3

Prompt for user input