Detect if homebrew package is installed

112
votes

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.

4
bashshellhomebrew
brew --cellar "$formula" >/dev/null 2>&1 --cellar formula: Display the location in the cellar where formula would be installed, without any sort of versioned directory as the last path. brew man page; would have loved to give it as an answer – 166_MMX
if [ ! -x "$(command -v PKG_EXEC)" ]; then # package not installed fi – JBallin

4 Answers

180
votes

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
fi

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.

7
votes

What about?

for pkg in macvim ngrep other needed packages; do
    if brew list -1 | grep -q "^${pkg}\$"; then
        echo "Package '$pkg' is installed"
    else
        echo "Package '$pkg' is not installed"
    fi
done
4
votes
# install if we haven't installed any version
brew ls --versions $lib || brew install $lib
# install if we haven't installed latest version
brew outdated $lib || brew install $lib
1
votes

Easiest two-liners: Step one, make sure it's installed

$ realpath . || brew install coreutils

This will print out the realpath of current dir, if not, then it will install it. And it will not fail even realpath not found.

Step two, call it in your actual code:

$ realpath ${someDir}