In Linux, the return command is used to exit a shell function or script. It is a built-in command that is supported by all Linux distributions.
The return command is used in the following syntax:
return [exit status]
The exit status is an integer that is used to indicate the success or failure of the shell function or script. The exit status can be any number from 0 to 255.
For example, the following shell function will print the message "Hello, world!" and then return the exit status 0:
function hello_world() {
echo "Hello, world!"
return 0
}
The following script will print the message "This is a script" and then return the exit status 1:
#!/bin/bash
echo "This is a script"
return 1
The return command is a useful tool for controlling the flow of execution in a shell function or script. It can be used to exit a function or script early, or to return an exit status to the calling function or script.
Here are some additional things to note about the return command:
- The
returncommand can only be used inside a shell function or script. - The
returncommand cannot be used in the interactive shell. - The
returncommand will always exit the shell function or script, even if it is nested inside another shell function or script. - The
returncommand can be used to return a non-zero exit status to the calling function or script. This can be useful for debugging or for signaling an error condition.
The return command is a versatile tool that can be used to control the flow of execution in a shell function or script. It is a built-in command that is supported by all Linux distributions.
return: return [n]
Return from a shell function.
Causes a function or sourced script to exit with the return value
specified by N. If N is omitted, the return status is that of the
last command executed within the function or script.
Exit Status:
Returns N, or failure if the shell is not executing a function or script.