CODEWITHSUNDEEP
bashshellunix
j--
j--

Reputation: 5666

What is the preferred way to check whether a program exists with bash

I am writing a script that will run several versions of a program written in different languages so it should be able to detect if the system can run a file first. I found this question somewhat useful, but I would like to know if my existing code could be improved instead.

I use the following approach to check if a program exists.

if type "$PROGRAM" >/dev/null 2>&1; then
  # OK
fi

I was debating whether this question should go in Code Review, but I decided to post it here as it's just 2 lines of code.

Upvotes: 1

Views: 99

Answers (1)

Sukima
Sukima

Reputation: 10064

I use this in bash:

# Convenience method to check if a command exists or not.
function command_exists {
  hash "$1" &> /dev/null
}

And that gives me a command_exists:

if command_exists "vim"; then
  echo "and there was great rejoicing!"
fi

Or in one offs:

command_exists "vim" && echo "and there was great rejoicing!"

function die {
  echo "$1"
  exit 1
}
command_exists "vim" || die "Vim needs to be installed"

Upvotes: 2

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