iltempo iltempo - 1 month ago 16
Bash Question

Detect if homebrew package is installed

I'm about to write a shell script to detect if several homebrew packages are installed in the system. Is there a way to use a brew command to achieve that?

I tried using the exit code of

brew install <formula> --dry-run
. But this builds the package if it is missing.

Answer

You can use

brew ls --versions myformula

to output the installed versions of the respective formula. If the formula is not installed, the output will be empty.

When using a recent versions of homebrew, which you can get with brew update, you can just run this (thanks Slaven):

if brew ls --versions myformula > /dev/null; then
  # The package is installed
else
  # The package is not installed
end

That said, it is probably a good idea to check for the existence of the tool at all and not just checking for the respective homebrew package (e.g. by searching for the executable in the $PATH). People tend to install tools in a rather large amount of ways in practice, with homebrew being just one of them.

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