Passing commands to subroutines

[citromatik]

Hi all,

I have encountered a code like this in a production program I couldn't make run:

use strict;
use warnings;

my $ref_file = $ARGV[0];

if (isReadableFile ($ref_file)) {
  executeComm ("cat $ref_file");
} else {
  print STDERR "$ref_file Does not exist\n";
}

## In a different module...

sub isReadableFile {
  my $file = shift;

  if (defined ($file) &&             # was a file name passed?
      ((-f $file) || (-l $file)) &&  # is the file a file or sym. link
+?
      (-r $file)                     # is the file readable?
     ) {
    return 1;
  }
  else {
    return 0;
  }
}

sub executeComm {
  my ($comm) = @_;
  print "$comm\n";
  system ($comm);
  print "$?\n";
}

A sample invocation should be something like:

$ perl test.pl file.txt

And if file.txt exists, is a regular file or links to a file and is readable, the command cat file.txt is executed inside the executeComm sub.

The problem arises when the file name or its path contains spaces:

$ perl test.pl file\ name.txt

This should be a valid invocation, but executeComm will receive the command cat file name.txt, and consequently, will fail. The same would happen if $ perl test.pl 'file name.txt' is passed, and perl test.pl 'file\ name.txt' would succeed, but the file tests on isReadableFile fail

A possible patch would be to escape every space after the file tests:

if (isReadableFile ($ref_file)) {
  $ref_file =~ s/ /\\ /g;  ###### Added
  executeComm ("cat $ref_file");
} else {
  print STDERR "$ref_file Does not exist\n";
}

But this seems a weak patch... Is this solution portable? Do you anticipate the appearance of more problems?, how would you solve this in production code?