grep -P no longer works. How can I rewrite my searches?
It looks like the new version of OSX no longer supports grep -P and as such has made some of my scripts stop working.
var1=`grep -o -P '(?<=<st:italic>).*(?=</italic>)' file.txt`
I need to capture the grep to a variable and I need to use the zero width assertions, as well as \K
var2=`grep -P -o '(property:)\K.*\d+(?=end)' file.txt`
Any alternatives would be greatly appreciated.
Answer
If your scripts are for your use only, you can install grep from homebrew-core using brew:
brew install grep
Then it's available as ggrep (GNU grep).
it doesn't replaces the system grep (you need to put the installed grep before the system one on the PATH).
The version installed by brew includes the -P option, so you don't need to change your scripts.
If you need to use these commands with their normal names, you can add a "gnubin" directory to your PATH from your bashrc like:
PATH="/usr/local/opt/grep/libexec/gnubin:$PATH"
You can export this line on your ~/.bashrc or ~/.zshrc to keep it for new sessions.
Please see here for a discussion of the pro-s and cons of the old --with-default-names option and it's (recent) removal.