exit is used to terminate the entire script or session, return only exits the function or the called script. exit is used to completely stop scripts or shells, and returns status codes for other programs to check; return is used to return from function or source scripts, and does not affect the execution of the entire script. When using exit, the script completely ends and returns control; when using return, only the current function is exited and the script continues to run. Using exit in an interactive shell closes the session, and return can only be used within a function or source file. Select exit to apply to situations where global termination is required, and select return to apply to scenarios where local exit and return results.

When you're writing or reading scripts—especially shell scripts or batch files—you'll often come across the commands exit and return . While they might seem similar at first glance, they serve different purposes depending on where and how they're used.

What exit really does

The exit command is used to terminate a script or shell session entirely. When you call exit in a script, it stops execution and returns control back to the system or the calling process. It can also return an exit status (like 0 for success or 1 for error), which other programs or scripts can check.

For example:

 if [ ! -f "myfile.txt" ]; then
  echo "File not found"
  exit 1
fi

In this snippet, if the file doesn't exist, the script exits with status code 1. This helps other processes understand what went wrong.

Also worth noting: using exit in an interactive shell (like your terminal) will close that session.

How return works differently

Unlike exit , the return command doesn't stop the whole script—it only exits from a function or a sourced script. That means if you're inside a function and you call return , it just goes back to where the function was called from, not the whole script.

Here's a simple example:

 my_function() {
  if [ "$1" -lt 10 ]; then
    echo "Value too low"
    return 1
  fi
  echo "Value is OK"
}

my_function 5

In this case, the function will print “Value too low” and return 1, but the script continues running after that. If you had used exit , the entire script would have stopped instead.

So return is useful when you want to pass back a result or status from a function or reusable block of code.

When to use one over the other

• Use exit when you want to completely stop a running script or shell.
• Use return when working within functions or sourced scripts and you just want to go back to the caller.

A few things to keep in mind:

• Using return outside of a function or sourced file may cause errors.
• Always consider whether your script needs to communicate a result via exit codes.
• In some environments like Windows batch files, exit can behave slightly differently, especially with options like exit /b .

So basically, think about scope: exit affects everything, return only affects the current context.

The above is the detailed content of What is the difference between exit and return in a script?. For more information, please follow other related articles on the PHP Chinese website!