Something like this can do:
use warnings;
use strict;
while(<DATA>){
chomp;
print $_,substr ($_,0,2),$/;
}
__DATA__
1234
5678
1000
1233
NOTE:I updated the code, since I was testing on an old Perl version before now.
If you tell me, I'll forget.
If you show me, I'll remember.
if you involve me, I'll understand.
--- Author
unknown to me