Still a good exercise for me to write it, and I assume for OP too.
First consider what systems you want your skills to be applicable for.
Do you need tools that work on many random Linux machines that you have little control over? Then go with the lowest common denominator - bash, and various command line tools (sed,awk,grep) included with every system, and get good with the subset of command line options common on all of them - most likely limited by the oldest system you need to work with. (There are still Windows XP and Redhat 4 systems out in the wild, if you're unlucky enough to have to work with them.)
Do you need to work with OS X at all? I never learned to use Apple's outdated versions of programs, instead I heavily customized my laptop to have compatible versions of things but this only works because there's 1 os x machine I ever deal with.
Then it's about the right tool for the right job. Do you want to process text? Awk will take you a long way, but ultimately, Perl is your friend. Do you want to want more structured programming type things (aka objects/classes)? Then Python is your friend. There's a certain mindset that thinks that if everything is in one language things are better, but that's a trap. With enough work, you can do the same thing in any language, but each languages is better than others at some specific thing. (working legacy code is that something that a language can be better at than others.)
These days, it's more important to learn what tools are available and how to use them, but because you can just google 'awk print second to last column' and plug that into your script, and continue working, there's less of a need to truely grok awk's language (for example). (I mean, spend the time to learn it once so it will come back to you the next time you need to do something more custom with it)
There’s no reason to chase X script/lang of the month. Bash etc are extremely well documented and there’s a very good chance someone already asked how to do something similar to what you’re doing on stackoverflow, etc.
Yet to find a GNU 'tr' alternative though
https://github.com/neosmart/tac
and `rewrite`, which I've been told is akin to gnu sponge, "rewritten" in rust:
Would recommend anyone to try it.
Thanks for that list! Is there any place where more of these "modern alternatives to coreutils" are collected?
I don't know whether anyone here has used Rexx. The 'parse' instruction in Rexx was incredibly powerful, breaking up text by field/position/delimiter and assigning to variables all in one line.
I've often wondered if there was a command-line equivalent. Awk is great but you have to 'program' the parsing spec, rather than declare it.
You could probably turn a declarative spec into an awk program with an awk program.
Delimeters/Regex:
$ perl -ne '($name,$pass,$uid,$gid,$therest)=split(/:/);print "$name $gid\n"' /etc/passwd
root 0
daemon 1
bin 2
...
$ printf "1234XY\n5678AB" | perl -ne '($f1,$f2)=unpack("a4 a2");print "$f2 $f1\n"'
XY 1234
AB 5678
When my one liners become 2-3 lines long I need to switch to a regular script, but I also log all my shell commands years back and have something a bit better than `history | grep word` to search it.</>
I'd be very interested to hear more about this.
single character
hck 1.494 ± 0.026s
hck (no-mmap) 1.735 ± 0.004s
choose 4.597 ± 0.016s
hck 2.127 ± 0.004s
hck (no-mmap) 2.467 ± 0.012s
choose 3.266 ± 0.011s
Of course, doing away with a pass is suppossed to give 2x, and I am wondering whether the regex constraint lead to this "side-effect".
[1] fast mode - https://github.com/sstadick/hck/blob/master/src/lib/core.rs#... https://github.com/sstadick/hck/blob/master/src/lib/core.rs#...
I see Negative index is currently "unlikely". I'm writing a similar tool [0], but with bash+awk. I solved the negative index support with a `-n` option, which changes the range syntax to `:` instead of `-` character.
My biggest trouble came with literal field separator [1], because FS can only be specified as a string in awk and backslash is a metacharacter for both string and regexp.
[0] https://github.com/learnbyexample/regexp-cut
[1] https://learnbyexample.github.io/escaping-madness-awk-litera...