lsof isn't something you automatically pickup if it's not your daily business (like so many other things). I for myself often forget about it but I have some usual ports to kill. So these days I simply search my shell history by port to find lsof again.
Back in the DOS era, there were few enough files on the system that I could just explore around and learn what everything did. That's no longer practical, but what's the alternative? There doesn't seem to be a "top 100 commands to get familiar with", or whatever. The ss64.com pages are pretty great, but...
Choose a random entry you don't recognise and open the man page for it. There's not that many on most systems - I mean, there's likely a couple hundred or more, but some are convenience symlinks and many you'll already know.
For things you may not have by default, there's a few "awesome" lists available, like https://github.com/agarrharr/awesome-cli-apps
What we really need is a tool like this for Windows. Find the process that keeps this file open and kill it. It's so annoying when I can't delete a file because some process has it open but I can't tell which one.
https://learn.microsoft.com/en-us/sysinternals/downloads/han...
https://learn.microsoft.com/en-us/windows/powertoys/file-loc...
Nevermind Windows, I want an app like this for android.
Its a good thing now we have chatGpt to help us :)