# [

> Check file types and compare values.
> Returns a status of 0 if the condition evaluates to true, 1 if it evaluates to false.
> More information: <https://www.gnu.org/software/bash/manual/bash.html#index-test>.

- Test if a given variable is equal/not equal to the specified string:

`[ "${{variable}}" {{=|!=}} "{{string}}" ]`

- Test if a given variable is [eq]ual/[n]ot [e]qual/[g]reater [t]han/[l]ess [t]han/[g]reater than or [e]qual/[l]ess than or [e]qual to the specified number:

`[ "${{variable}}" -{{eq|ne|gt|lt|ge|le}} {{integer}} ]`

- Test if the specified variable has a [n]on-empty value:

`[ -n "${{variable}}" ]`

- Test if the specified variable has an empty value:

`[ -z "${{variable}}" ]`

- Test if the specified [f]ile exists:

`[ -f {{path/to/file}} ]`

- Test if the specified [d]irectory exists:

`[ -d {{path/to/directory}} ]`

- Test if the specified file or directory [e]xists:

`[ -e {{path/to/file_or_directory}} ]`