perl -le "$f='hello world'; $f=~s!^.!!; print $f"
perl -le "$f='hello world'; $f=~s!.!!; print $f"

##</code><code>##

perl -le "$f='hello world'; $f=~s!^.!!s; print $f"
perl -le "$f='hello world'; $f=~s!.!!;s print $f"