Sloth is a native Mac app that shows all open files and sockets in use by all running processes on your system. This makes it easy to inspect which apps are using which files and sockets.
Sloth is essentially a friendly, exploratory GUI built on top of the
lsof command line tool. The output is parsed and shown in a searchable, filterable outline view with all sorts of convenient additional functionality. See screenshots below.
Sloth is free, open source software and has a home on GitHub. It has been continuously developed and maintained for a very long time (since 2004). If you find this program useful, please make a donation.
You can download the latest version here:
Sloth can also be installed via Homebrew (may not be latest version):
Older versions supporting macOS 10.8 and earlier can be downloaded here.