41–50 of 159 posts
I was really happy about tac when I found out about it, same with paste and comm as already mentioned. Gotten a lot of mileage out of the various seldom used options of uniq, diff and cut too.
Earlier quoted context omitted.
Actually not, since these GNU tools could be used on BSD as well.
GNU tools? Original column and factor is older than the GNU project. Don't attribute everything to that bearded madman. GNU is mostly just a copycat of already free software.
Though a better title for this particular post would be "POSIX" utilities.
> Don't attribute everything to that bearded madman.
And yet the bearded madman has done a lot more than you probably have.
I was really happy about tac when I found out about it, same with paste and comm as already mentioned. Gotten a lot of mileage out of the various seldom used options of uniq, diff and cut too.
tac, but also rev. I can't think of an example right now, but that's been useful as well.
Earlier quoted context omitted.
Many people chain ps and grep... pgrep does that
That's not a great example as `pgrep` is a little more nuanced than running `ps [options] | grep [string]`, eg you cannot use many of the same `ps` flags `pgrep` like you can with `ps`. At least with "in appropriate use of cat" (as some call it) you're literally just swapping the stdin file stream with a disk io file stream so there's no functional difference what-so-ever. I'm not saying I agree with the GP either th…
amirite?
pgrep often fails me I think mostly for apps the edit their cmdline and it needs to whole word match I think?
Earlier quoted context omitted.
Many people chain ps and grep... pgrep does that
That's not a great example as `pgrep` is a little more nuanced than running `ps [options] | grep [string]`, eg you cannot use many of the same `ps` flags `pgrep` like you can with `ps`. At least with "in appropriate use of cat" (as some call it) you're literally just swapping the stdin file stream with a disk io file stream so there's no functional difference what-so-ever. I'm not saying I agree with the GP either th…
If you mean adding a 'cat' at the start to provide a clear entry-point for the data, you can actually put the redirect at the beginning:
cheesy_lines.txt
Also paste
* 'comm -3' is a quick way to do a set difference from the command line. * Newer versions of sort have an option for running sorts in parallel. If you're using an older sort, you can split the files, sort them individually with GNU parallel, and use --merge to combine them. * If you have scripts that read data files, process them, and output more files, consider using a Makefile. * tmux is a good way to leave a devel…
Dear sweet hypnotoad, don't use Makefiles for this. Scripts in a pipeline are perfectly well suited for ETL. They have the advantage of using the same language as the command language (Makefile is not shell, and when it differs it's a significant surprise). Plus, you can drop a script into a dir in your PATH and it will work in any project.
Use make if you have a project which expensively computes assets and reusing partial outputs is possible.
> pushd and popd are useful in shell scripts to temporarily change directories without forgetting where you were.
I would start with
cd - # go back to where I just came from
Really, there's a whole separate set of skills for effective interactive shell use & writing great bash scripts (e.g. parameter expansion and history manipulation).
It always pains me when I see people use "cat" left and right, even when they don't need it. This makes for good reading: http://porkmail.org/era/unix/award.html
Once I saw this notation, I immediately fell in love: output.txt
cat file-that-doesnt-exist.txt | less
You get a nice error message:
cat: 'file-that-doesnt-exist.txt': No such file or directory
Don't forget the often overlooked "apropos"!