sed

I can't believe it's not butter

remove all lines except matching one

let's say you've got this file with sha hashes and you want to verify just one file of it (and you're using a version of sha256sum which can't just ignore/skip missing files):

8edf5e31e28c5e56df3f87334d193cc777f241481ba091930ec53220b01c135d  yt-dlp.exe
e35bc18f766fd61ed46a42913f89680d5ea1d714135898eb6df5cd9248213ccc  yt-dlp_x86.exe
25cc412d1d3c0725a1f2f5b7e4682f6fb40e6d15f7024e96f7afd572e9919535  yt-dlp
ae08e0b56fea59a8bfdadacd92eddc9bdfdc1473199178cb4e31bacfd991864a  yt-dlp.tar.gz
5bd59c0b95740cfd667b12c627b93c0031e1d4e2fbb3e09b7ede293b48757bee  yt-dlp.zip

I just want the line containing the yt-dlp hash, not the .zip, .tar.gz etc.

sed -i '/yt-dlp$/!d' filename.txt

remove after match

example: foo:1234, I want to get rid of :1234

echo foo:1234 | sed 's/\:.*//'

remove empty lines

sed '/^$/d'

append to end of line

I want to add a comma , to the end of every line

sed 's/$/,/'

remove spaces

sed 's/ //'