XTee: eXecute Tee

A utility to filter input via a regular expression, and pass this input into a program.

Intended use is to use this in combination with git push as follows:

git push -o merge_request.create 2>&1 | xtee -p "https://\\S+" -e wl-copy >&2

Which should pass the stderr of git push to the stdin of xtee. xtee will filter out any URLs via the https regex, and forward it to wl-copy which copies it to the clipboard. The output of git push usually includes a merge request URL if you create one via the push flags. I want to grab these URLs as this output is generated in the background. Since I use nvim this text is hard to copy, since it appears in a notification that is removed when I click on it.

Since xtee will "tee" the output to stdout as well, it should still show up. Since I stole the stderr, I want to dump the output back to stderr, not sure if that makes a difference for how nvim displays these messages.

An important requirement is that text should be "live" fed to stdout without much buffer delay, so that I can see my push progress. Any escape sequences should be unmodified so that git push will correctly render progress bars.