For some reason it is not working with single quotes but once I put double quotes in the .zshrc it started working: alias update="brew update; brew upgrade; brew cu -ay; brew cleanup; pip install --upgrade `pip list --outdated | awk 'NR>2 {print $1}'`" Also, the pip one will result in error if all the packages are up to date. I am on macOS Catalina 10.15.6