What are perl4 and perl5, are there any differences?
Perl4 and perl5 are different versions of the language. Perl4 was the previous release, and perl5 is “Perl: The Next Generation.” Perl5 is, essentially, a complete rewrite of the perl source code from the ground up. It has been modularized, object oriented, tweaked, trimmed, and optimized until it almost doesn’t look like the old code. However, the interface is mostly the same, and compatibility with previous releases is very high.
