learnbyexample

learnbyexample @programming.dev 11mo ago

Why would it print the colon?

1

learnbyexample @programming.dev 11mo ago

Regex syntax and features vary between implementations. \d isn't supported by BRE/ERE flavors.

GNU grep supports PCRE, so you can use grep -oP '/dev/loop\d' or grep -o '/dev/loop[0-9]' if you are matching only one digit character.

learnbyexample @programming.dev 1y ago

Thanks a lot for the feedback :)

learnbyexample @programming.dev 1y ago

Already done grep, sed, coreutils, cli basics and more. See https://learnbyexample.github.io/learn_gnuawk/buy.html#book-list for links.

1

learnbyexample @programming.dev 1y ago

Well, if you are comfortable with Python scripts, there's not much reason to switch to awk. Unless perhaps you are equating awk to Python as scripting languages instead of CLI usage (like grep, sed, cut, etc) as my ebook focuses on. For example, if you have space separated columns of data, awk '{print $2}' will give you just the second column (no need to write a script when a simple one-liner will do). This of course also allows you to integrate with shell features (like globs).

As a practical example, I use awk to filter and process particular entries from financial data (which is in csv format). Just a case of easily arriving at a solution in a single line of code (which I then save it for future use).

learnbyexample @programming.dev 1y ago

I'll recommend some from the lesser known progression fantasy genre:

Cradle by Will Wight
Mage Errant by John Bierce
Mother of Learning by Nobody103 (Domagoj Kurmaić)
The Weirkey Chronicles by Sarah Lin
Beware of Chicken by CasualFarmer
Super Powereds by Drew Hayes

learnbyexample @programming.dev 1y ago

Not my site, just sharing a link I saw on HN.

learnbyexample @programming.dev 1y ago

Well, I'm not going to even try understanding the various features used in that sed command. I do know how to use basic loops with labels, but I never bothered with all the buffer manipulation stuff. I'd rather use awk/perl/python for those cases.

2

learnbyexample @programming.dev 1y ago

This might work, but I think it is best to not tinker further if you already have a working script (especially one that you understand and can modify further if needed).

        perl -pe 's/\[[^]]+\]\((?!https?)[^#]*#\K[^)]+(?=\))/lc $&=~s:%20|\d\K\.(?=\d):-:gr/ge'

1

learnbyexample @programming.dev 1y ago

Hmm, OP mentioned "Only edit what’s between parentheses" - don't see anywhere that whole URL shouldn't be changed...

7

learnbyexample @programming.dev 1y ago

Here's a solution with perl (assuming you don't want to change http/https after the start of ( instead of start of a line):

        perl -pe 's/\[[^]]+\]\(\K(?!https?)[^)]+(?=\))/lc $&=~s|%20|-|gr/ge' ip.txt

e flag allows you to use Perl code in the substitution portion.
\[[^]]+\]\(\K match square brackets and use \K to mark the start of matching portion (text before that won't be part of $&)
(?!https?) don't match if http or https is found
[^)]+(?=\)) match non ) characters and assert that ) is present after those characters
$&=~s|%20|-|gr change %20 to - for the matching portion found, the r flag is used to return the modified string instead of change $& itself
lc is a function to change text to lowercase

1

learnbyexample @programming.dev 1y ago

GNU datamash (https://www.gnu.org/software/datamash/alternatives/) - handy tool for data munching. There's also https://github.com/BurntSushi/xsv

learnbyexample @programming.dev 1y ago

Check out my chapter on GNU grep BRE/ERE for those wanting to learn this regex flavor: https://learnbyexample.github.io/learn_gnugrep_ripgrep/breere-regular-expressions.html (there's also another chapter for PCRE)

learnbyexample @programming.dev 1y ago

Memory, Sorrow, and Thorn by Tad Williams

learnbyexample @programming.dev 1y ago

I use Vim ;)

Python itself provides IDLE, which is good enough for beginners. https://thonny.org/ is another good one for beginners.

As mentioned by others, Jetbrains is good for many languages. https://www.kdevelop.org/ is another option.