Question

I have the following in my .bashrc to print a funny looking message:

fortune | cowsay -W 65

I don’t want this line to run if the computer doesn’t have fortune or cowsay installed.

What’s the best or simplest way to perform this check?

Answer 1

You can use type or which or hash to test if a command exists.

From all of them, which works only with executables, we’ll skip it.

Try something on the line of

if type fortune &> /dev/null; then
    if type cowsay &> /dev/null; then
        fortune | cowsay -W 65
    fi
fi

Or, without ifs:

type fortune &> /dev/null && type cowsay &> /dev/null && (fortune | cowsay -W 65)