You are testing whether a file called BADSYMS is zero sized (if (-z BADSYMS)), but trying to remove a file called BADSYMS.out. You're not quoting the filename in this line either.

Also, there's no need to fork off a shell for rm. Use Perl's builtin unlink instead.

Try this:

use strict;
use warnings;

if (-z 'BADSYMS.out') {
    unlink 'BADSYMS.out' or die 'Could not delete BADSYMS.out';
} else {
    print "Bad symbols contained in BADSYMS.out\n";
}
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2 important notes on the error check.

First of all you should make sure that your die message contains the output of $!, the operating system error will often greatly simplify debugging.

Secondly I suggest putting the name of the file into a variable and using that variable in both the open and the die. The reason is that otherwise it is far too easy for someone to come along and change what file is being opened but not edit the error check. That can be a real pain to debug. When you can, you want to reduce the need to synchronize code...

I opened the file using

unless (open (BADSYMS, ">BADSYMS.out")) {
                         die ("Can't open output file BADSYMS.out\n");
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So i presumed that when using the -z I could test against the filehandle, do I need to use the quotes?

Now I get this error message

Can't exec "BADSYMS.out": Permission denied
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This is the code I now have in:

if (-z `BADSYMS.out` ) {
#       unlink `BADSYMS.out` or die `Cant delete BADSYMS.out`;
        print "hi";
}
        else { print "Bad symbols contained in BADSYMS.out\n"; }
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I have commented out the unlink, as it was going straight to it, regardless of whether the file was 0 or not. When it prints out the "hi" regardless I know the -z isn't working

any ideas?

Don't use backticks like `BADSYMS.out` - instead use normal single or double quotes:

if (-z "BADSYMS.out") {
  # do something
}
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The backticks try to execute the file which is not what you want.

-- Hofmator

It looks like you apply the test to an open filehandle and then try unlinking with the same handle. Unlinking should be done on the filename. The -z test should be done after the filehandle is closed to ensure all data is written. Unlinking an open file is Not Good. This is better:

# assumes the file is named in a variable $badsyms.
# $badsyms  would best be an absolute path.
#
# close(BADSYMS); before this, otherwise writes may not be
# flushed before the test.
# That would give a false positive

if ( -z $badsyms ) {
    unlink $badsyms or die "Cannot unlink $badsyms: $!";
}
else {
    print "Bad symbols contained in $badsyms\n";
}
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Update: Added death on error.

Update₂: Re AM's followup The BADSYMS filehandle is already closed. Replace with "BADSYMS.out" in the -z test.

After Compline,
Zaxo

Hi, now I am using:

close (BADSYMS);

if (-z BADSYMS ) {
        unlink "BADSYMS.out" or die ("Cant delete BADSYMS.out");
        print "hi";
}
        else { print "Bad symbols contained in BADSYMS.out\n"; }
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What happens now is when the file is zero or not zero, the if part is skipped, and it goes straight to the else. When the file is non-zero a message is returned:

Stat on unopened file <BADSYMS> at test.pl line 317
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The filenames are assigned at the start of the script

unless (open (BADSYMS, ">BADSYMS.out")) {
                die ("Can't open output file BADSYMS.out\n");
        }
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This isn't in a loop as such, the script runs and the file maybe written to, if it isn't and therefore is empty, I want to delete it. If it is written to I want the print statement to output the name.

Thanx, Martin

Your problems are 1) you close the file handle then try to test it. 2) You can't unlink an file that has an open filehandle on many systems. This should be self explanatory code. $file is the FILE NAME. We open this file onto the FILE HANDLE called BAD. We can then read from the file through the filehandle.

$file = "bad.out";

open BAD, $file or die "Oops can't open $file Perl says $!\n"

# do stuff to BAD

close BAD;

if ( -s $file ) {
    # file has size
} else {
    # file has zero size
    unlink $file or die "Can't unlink $file: $!\n";
}
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PS Get a login! cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

You can use the filetest operators on either a filename or a FILEHANDLE. Here is a demo, save it as whatever. It opens itself, tests for file size against its name and FH (both the same) and then unlinks itself:

open SELF, $0 or die "Can't open myself $!\n";

print "My name is $0\n";
print "I am ", -s SELF, " bytes\n";
print "That's ", -s $0, " bytes\n";

close SELF;
unlink $0 and die "Deleted myself, I'm outta here!\n";
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cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

if (-z "BADSYMS.OUT") {
    system("rm BADSYMS.OUT");
} 
else {
    print "Bad symbols...";
}
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Update: Too slow once again, and tomhukins used strict and unlink plus error checking which I should have used, too. Shame on me :)

Regards...	Stefan
you begin bashing the string with a +42 regexp of confusion