In my experience the use of backticks or system to do what Perl can do indicates a lack of quality—there are often problems lurking in the rest of the code since the original programmer didn’t know Perl very well. Here be dragons. If you look at it funny, it might break.

I stopped writng awk scripts the day I learned Perl. There’s nothing that awk can do that cannot be easily done in Perl. I find grep handy from the command line and do simple sed calls from shell scripts and Makefiles. I am never tempted, however, to call them from Perl.

For added fun, consider that different implementations of awk, grep, and sed have incompatible feature sets and regular expression syntax.