$ perl -w a.pl
Variable "$a" is not available at (eval 1) line 2.
Use of uninitialized value in print at a.pl line 11.
a=
Variable "$b" is not available at (eval 2) line 2.
Use of uninitialized value in print at a.pl line 11.
b=
Variable "$c" is not available at (eval 3) line 2.
Use of uninitialized value in print at a.pl line 11.
c=