test file with trailing whitespace

[nix45]

I'm trying to help a friend write a simple Perl script that will test whether or not a file exists or not, and if it does, write the name of the file in a file called exists.txt. The files that don't exist go in nonexist.txt. The script reads the names of the files from a file that looks like this...

"/etc/samba/smb.conf"
"/etc/nonexistent file"
"/usr/doesnt_exist"
"/var/log/messages"

Now, my script works perfect, except the problem is that some of his files have trailing whitespace at the end of the filename.

#!/usr/bin/perl -w

$a = '/root/testing/a.txt';
open(FILE, $a) or die "Can't open file: $!\n";
@lines = <FILE>;
close FILE;

$exists = '/root/testing/exists.txt';
open(EXISTS, ">$exists") or die "Couldn't open exists.txt for writing: $!\n";

$nonexist = '/root/testing/nonexist.txt';
open(NONEXIST, ">$nonexist") or die "Couldn't open nonexists.txt for writing: $!\n";

foreach (@lines) {
 $_ =~ s/"//g;
 chomp;
 if (-e $_) {
   print "$_ exists\n";
   print EXISTS "$_\n";
 } else {
   print "$_ doesn't exist\n";
   print NONEXIST "$_\n";
 }
}

How do you test if a file exists when it has trailing whitespace at the end?


Thanks,
Chris

 

[rharsh]

This will clean the leading and trailing spaces off of a line of text.

my $string = '   Some String    ';
print "\|$string\|\n";
print "\|" . &trim($string) . "\|\n";

sub trim ($) {
	$_ = shift @_;
	chomp;
	s/^\s+//;
	s/\s+$//;
	return $_;
}

 

[PaulTEG]

if (-e (trim($_)) {
...


sub trim {
    my @out= @_;
    for (@out) {
        s/^\s+//;
        s/\s+$//;
    }
    return wantarray ? @out : $out[0];
}

HTH
--Paul