if

Performs conditional processing in shell scripts. See also: test, [. More information: https://www.gnu.org/software/bash/manual/bash.html#Conditional-Constructs.

if condition_command; then echo "Condition is true"; fi

if ! condition_command; then echo "Condition is true"; fi

if condition_command; then echo "Condition is true"; else echo "Condition is false"; fi

if [[ -f path/to/file ]]; then echo "Condition is true"; fi

if [[ -d path/to/directory ]]; then echo "Condition is true"; fi

if [[ -e path/to/file_or_directory ]]; then echo "Condition is true"; fi

if [[ -n "$variable" ]]; then echo "Condition is true"; fi

man [