I love the Linux command line. I don’t know how to categorize the tips I have collected so I’m dumping them here for the time being.
The newer netstat
In the old days I used to constantly do
$ netstat -an|grep LISTEN|grep <PORT>
to see what tcp ports I had processes listening on. While that is very helpful, it doesn’t tell you the listening process. A better approach:
$ lsof -i tcp:<PORT>
Repeat last argument
I am constantly doing things like
$ grep <string> <big-file> > /tmp/results
and then I want to have a look at that file but I don’t want to type in
$ more /tmp/results
so what do I do?
I type this to give me the last argument:
$ more !$
My fingers have memorized that pattern and so I do it without conscious thought, and you’re holding down the SHIFT key so it can be typed very quickly.
But sometimes I can’t wait to type even that. I want to collect the grep results into a file in case there were a lot of matches, but I also want to see the matching results on my screen as soon as they are available. What do I do? Use tee, as in:
$ grep <string> <big-filez> |tee /tmp/results|more
More Obscure stuff
A cool blog with lots of good, obscure tips, generally more technical than the ones above, is https://die-computerhilfe.de/blog
To be continued…