Difference Between myscript || exit 0 and myscript || true

NOTE

I've referred to the A Clean Exit blog post, #170 and #171.

When writing or running shell scripts, the || operator is commonly used to handle cases where a specific command fails. The || operator is designed to execute the command on its right only when the preceding command fails. At first glance, myscript || exit 0 and myscript || true might seem similar, but they have subtle differences, especially regarding the behavior of || true across different platforms.

1. myscript || exit 0

exit 0 immediately terminates the script while returning a successful exit code (0).

TIP

• exit 0 → success
• exit 1 → failure

In this case, if myscript fails (i.e., returns a non-zero exit code), exit 0 is executed, marking the script as "successfully terminated" despite the failure. This approach can be useful in scenarios like CI/CD pipelines where errors need to be ignored, and the process should continue or be logged as successful.

sh -c "myscript || exit 0"

The above command ensures that even if myscript fails, the script returns exit code 0, allowing subsequent processes to treat it as a success.

2. myscript || true

true is a command in Linux/Unix(POSIX) systems that always returns a successful exit code (0). When using myscript || true, even if myscript fails, true will execute and return a successful exit code (0).

However, unlike exit 0, true does not terminate the current script; it merely returns a success status, allowing the rest of the script to continue execution.

sh -c "myscript || true"

In this case, if myscript fails, true is executed, ensuring an exit code of 0, but the script continues running.

3. Cross-Platform Behavior

|| true works as expected on POSIX-compliant shells (e.g., bash, zsh) and Git Bash. However, it does not work in Windows PowerShell or CMD.

For Windows environments using PowerShell or CMD, the || true syntax is unsupported, and you should use alternatives like || exit 0.

4. Key Differences Summary

Aspect	myscript || exit 0	myscript || true
On Failure	Terminates the script (exit) with a success code (0)	Returns a success code (0) and continues execution
Script Flow Control	The script immediately stops	The script continues running
Compatibility	Works in both POSIX and Windows environments	Works only in POSIX and Git Bash; not in PowerShell or CMD
Use Case	Ignoring errors and terminating execution	Ignoring errors and proceeding to the next command

5. Practical Examples

• myscript || exit 0:

  nodemon --exec "mocha bad.test.js || exit 0"

  In this example, if the tests fail, exit 0 ensures the script exits successfully, allowing nodemon to continue restarting. This approach works in all POSIX and Windows environments.

• myscript || true:

  npm install || true

  This command ensures that even if some errors occur during the installation, the script will continue executing. However, this approach works only in Git Bash or Linux environments and will not work in Windows PowerShell or CMD.

6. Conclusion

myscript || exit 0 terminates the script on failure but treats it as a success, while myscript || true ignores the failure and allows the script to proceed. However, since || true is specific to POSIX-compliant environments, Windows users must find suitable alternatives like || exit 0 for compatibility.

Choosing the right approach for your environment is key to ensuring proper script behavior. I hope this explanation helps you understand the differences between || exit 0 and || true!