if (1) - Linux Manuals

if: conditionally execute a command

NAME

if - conditionally execute a command

Synopsis

if CONDITION; COMMANDS_TRUE...; [else; COMMANDS_FALSE...;] end

Description

if will execute the command CONDITION. If the condition's exit status is 0, the commands COMMANDS_TRUE will execute. If the exit status is not 0 and else is given, COMMANDS_FALSE will be executed.

In order to use the exit status of multiple commands as the condition of an if block, use begin; ...; end and the short circuit commands and and or.

The exit status of the last foreground command to exit can always be accessed using the $status variable.

Example

if test -f foo.txt
        echo foo.txt exists
else
        echo foo.txt does not exist
end

 will print foo.txt exists if the file foo.txt exists and is a regular file, otherwise it will print foo.txt does not exist.