Use of uninitialized value $lines_0 in concatenation (.) or string at test.pl line 62.
This is the content of lines_0: 
Use of uninitialized value $lines_1 in concatenation (.) or string at test.pl line 63.
This is the content of lines_1: 
Use of uninitialized value $lines_2 in concatenation (.) or string at test.pl line 64.
This is the content of lines_2:
Use of uninitialized value $lines_3 in concatenation (.) or string at test.pl line 65.
This is the content of lines_3: