run-executable-with-no-file-name-extension

Run executable with no file name extension

Run executable with no file name extension.

Yes:

$ foo

No:

$ foo.sh
$ foo.bash
$ foo.zsh
…

Executables should omit file name extensions, such as .sh or .bash or .zsh.

This is because an executable file name extension is unnecessary, and also easy accidentally set incorrectly. For example, we have some customers with scripts that show the extension .sh yet the scripts require functionality of bash.

Shebang

To ensure which shell is needed, write the first line of the script as a shebang such as these below.

For a script that can run on any POSIX current shell:

#!/usr/bin/env sh

If your script must use the bash shell then use:

#!/usr/bin/env bash

If your script must use the zsh shell then use:

#!/usr/bin/env zsh

Exceptions

If you know what you're doing, then there are some rare times you may want to specify a file name extension, or specify a shell using shebang that isn't an actual script requirement.

For example, we have some customers who want to have shell-specific scripts, such as for optimizations, or deployments to different systems with different default shells. For example, one customer has foo.sh and foo.bash and foo.zsh all in the same directory; the deployment process chooses which script is deployed to which systems.