Question

I’ve got a problem in my Perl program when I try to combine a computer name in a string with a string with dot (.), please see the code below.

#!/usr/bin/perl
use strict;
use warnings;

chomp(my $COMPUTERNAME = `hostname`); #this should give the computername e.g CH-B7G33
my $complog = $COMPUTERNAME.".log"; 
print "$complog";

The expected output would be.

CH-B7G33.log

But what I got is wrong, it printed out.

.logB7G33

Did I do something wrong in the code? Please help me, I’m a Perl beginner and by the way sorry to my English.

Answer 1

The return value from your system call contains a \r at the end, which chomp is not clearing away. So your string ends up looking like CH-B7G33\r.log which when printed causes the terminal to display CH-B7G33 then move the cursor back to the start of the line, and then display .log which overwrites the characters, leading to the incorrect output you saw.

Using a substitution works well, and will handle both \r and \n line endings (and other trailing space, as written here).

(my $COMPUTER_NAME = `hostname`) =~ s/\s+$//;