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if — Perform conditional processing in shell scripts. See also: `test`, `[`. More information: <https://w

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

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Problem

How to use the if command: Perform conditional processing in shell scripts. See also: test, [. More information: <https://www.gnu.org/software/bash/manual/bash.html#Conditional-Constructs>.

Solution

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

Execute the specified commands if the condition command's exit status is zero:

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

Execute the specified commands if the condition command's exit status is not zero:

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

Execute the first specified commands if the condition command's exit status is zero otherwise execute the second specified commands:

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

Check whether a [f]ile exists:

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

Check whether a [d]irectory exists:

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

Check whether a file or directory [e]xists:

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

Check whether a variable is defined:

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

List all possible conditions (test is an alias to [; both are commonly used with if):

man test

Code Snippets

Execute the specified commands if the condition command's exit status is zero

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

Execute the specified commands if the condition command's exit status is not zero

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

Execute the first specified commands if the condition command's exit status is zero otherwise execute the second specified commands

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

Check whether a [f]ile exists

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

Check whether a [d]irectory exists

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

Context

tldr-pages: common/if

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