Advantages

Perl derives most of its syntax from well-known languages and tools common in UNIX-like operating systems.

Becoming a good programmer with Perl, with previous knowledge of C, Shell script, Sed, Awk and other UNIX tools is relatively easy. Perl is really easy to learn!

Perl with CPAN has a module to do pretty much anything you'd ever want to do and even more for things you probably don't want to do.

Perl is a very entraining language to work (like C or Assembly) because of the freedom it provides.

Perl is stable and predictable - it just requires basic UNIX knowledge and decent Perl intuition.

Finally, Perl has developed text processing capabilities to the extreme - You want to strip newlines from input? Check it out:

$_ = do { local $/; <> };
s/[\n\r\t ]+//g;
print;

As you can see, it's pretty simple and compact!