til/unix/check-if-command-is-executable-before-using.md

Check If Command Is Executable Before Using

When writing a quick bash script, you may want to check if a command exists and is executable before trying to call it. This can be done with command, a builtin shell command, and the -v flag.

If the -V or -v option is supplied, the exit status is 0 if command was found, and 1 if not.

Knowing that, we can redirect the output of the command to /dev/null and then short-circuit executing the command if it's not available.

command -v pbcopy >/dev/null 2>&1 && echo 'something' | pbcopy

In this example, I execute the pbcopy command, which copies text to my system clipboard, only if that command is available and executable.

See man bash and find the listing for command for more details.