dev > perl

A major reason I use Perl is because it allows my scripts to be portable across the many computers that I work on.

Perl comes preinstalled on Linux, Solaris, AIX, and HP-UX, including older versions of those OS's.

I contend that Perl is so widespread that Autotools could replace its Bourne shell scripts with Perl scripts. Well, that's not completely true — Bourne shell is certainly installed in some places that Perl isn't. But Perl really is awfully widespread.

what scripting languages come preinstalled?

Perl Python Bourne ksh88 Bash
RHEL 6 v5.10.1 v2.6.6
5 v5.8.8 v2.4.3
Solaris 11 v5.10.0 v2.6.4
10 v5.8.4 v2.3
9 v5.6.1 x
8 v5.005_03 x
AIX 6.1 v5.8.2 x
HP-UX 11.31/IPF v5.8.8 x
OS X 10.8 v5.12.4 v2.7
10.3 v5.8.1 v2.3
10.2 v5.6.0 v2.2