I then tried the File::Spec module. It helps.

$me = "dirtest3";

# Perl script to test variations on file/dir test argument quoting

use File::Spec;

print "All of the following conditions are true on my system.\n";
print "The issue is to see which tests work.\n";
print "The final path includes a directory name containing a space.\n"
+;
print "\n";


$part1 = "C:";
$part2 = "users";
$part3 = "public";
$part4 = "Music";
$part5 = "Sample Music";
$full = File::Spec->catfile( $part1, $part2, $part3, $part4, $part5 );

print "\nThese tests use a path consisting of concatenated substrings:
+\n";
print "  full = '$full'\n";
print "\n";


$expl = "Full path, unquoted";
if ( -e $full )
{ print "'-e $expl' is true\n"; } else { print "'-e $expl' is false\n"
+; }

$expl = "Full path in single quotes";
if ( -e '$full' )
{ print "'-e $expl' is true\n"; } else { print "'-e $expl' is false\n"
+; }

$expl = "Full path in double quotes";
if ( -e "$full" )
{ print "'-e $expl' is true\n"; } else { print "'-e $expl' is false\n"
+; }
[download]

Again, I was a bit surprised at the second case. But I can use one of the other two cases.

All of the following conditions are true on my system.
The issue is to see which tests work.
The final path includes a directory name containing a space.


These tests use a path consisting of concatenated substrings:
  full = 'C:\users\public\Music\Sample Music'

'-e Full path, unquoted' is true
'-e Full path in single quotes' is false
'-e Full path in double quotes' is true
[download]