The regular expression syntax; sigils on (some) variables; shortcuts like `bar if foo`; optional parenthesis on function calls; `chomp()` and `chop()`; those are just a few things that come to mind.

Ruby has since forever been described as a cross between Perl and Smalltalk (and some other languages), including by its creator (Matz).

Read up on Matz's account of how he developed Ruby and what were his influences. Larry Wall was top his list.