ccryx [he/him]

kmail is in the arch repository (in extra), the package is called kmail.

I know you asked about sed, but in case grep is fine, too:

echo theString | grep -f <file with patterns>

Not sure if there’s an output which pattern matched.

Thanks for reminding me to finish reading that book!

Sourceforge has stopped distributing adware installers again since they changed ownership a few years ago.