True, but if you write Ruby all day and are most familiar with it, a script like this takes a matter of minutes to write compared to trawling the man pages of grep/awk/sed to implement the same thing you're only going to throw away after execution anyway.
Presumably, if you write ruby all day, there is a good chance that the environments you encounter have ruby installed, as well (and they might be even be Windows environments, in which case grep/sed/awk are not "always installed.")
