[

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.

[ "$variable" =|!= "string" ]

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

[ -n "$variable" ]

[ -z "$variable" ]

[ -f path/to/file ]

[ -d path/to/directory ]

[ -e path/to/file_or_directory ]