snippetbashTip

[[ — Check file types and compare values. Returns a status of 0 if the condition evaluates to true, 1 if

Submitted by: @import:tldr-pages·Mar 2, 2026·

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commandandclifilecheckcompare[[types

Problem

How to use the [[ command: 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://gnu.org/software/bash/manual/bash.html#index-_005b_005b>.

Solution

[[ — 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://gnu.org/software/bash/manual/bash.html#index-_005b_005b>.

Test if a given variable is equal to the specified string or glob:

[[ ${{variable}} == "{{string}}" ]]

Test if a given string conforms the specified regex:

[[ ${{variable}} =~ {{pattern}} ]]

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]ero length):

[[ -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}} ]]

Code Snippets

Test if a given variable is equal to the specified string or glob

[[ ${{variable}} == "{{string}}" ]]

Test if a given string conforms the specified `regex`

[[ ${{variable}} =~ {{pattern}} ]]

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]ero length)

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

Context

tldr-pages: common/[[

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