test, [ ] and [[ ]] — checking conditions
cheat sheet · Ubuntu 24.04 · bash 5.2 · dash 0.5 https://lab.dimsanych.ru/en/wiki/test-conditions/Cheat sheet
-
[ -f /etc/app.conf ] && echo "file exists" -
[ -d "$dir" ] || mkdir -p "$dir" -
[ -z "$1" ] && { echo "Usage: $0 FILE" >&2; exit 2; } -
[ "$answer" = yes ]strings are equal -
[ "$count" -gt 10 ]number greater than 10 -
[ -r "$f" ] && [ -s "$f" ]readable and not empty -
[[ $name == *.log ]]pattern, bash only -
[[ $ver =~ ^[0-9]+\.[0-9]+$ ]]regular expression, bash only
Options
The test checks are in the table below. The full list is in help test; for
[[ ]], see man bash, section CONDITIONAL EXPRESSIONS.