Is grep (or better: egrep) a good starting point for examples? or:

perl -ne 'print if /xyz/' file
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In my "Introduction into Perl" (available in German at my Homepage - Talks called "Einführung in Perl" -> PDF), I try to give an introduction into REs at the end, and with some additional examples (e.g. how to check a date or ip address) we try to build together most of the pupils understand it rather fast. If you want to use it (and perhaps translate it), go on