The updates don't help any. The question I asked in my original post remains. How can you tell where a file name ends? What you ask is not possible, unless you impose extra restrictions. Let's say the file contains the line:

C:\Program Files\Application Name\bin\app.exe > C:\Program Files\Appli
+cation Name\log\app.log do_it 2> C:\Program Files\Foo Bar\log\app.log
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Should the above return:

C:\Progra~1\Applic~1\bin\app.exe > C:\Progra~1\Applic~1\log\applog~1 2
+> C:\Progra~1\FooBar~1\log\app.log
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Probably not. You probably wanted:

C:\Progra~1\Applic~1\bin\app.exe > C:\Progra~1\Applic~1\log\app.log do
+_it 2> C:\Progra~1\FooBar~1\log\app.log
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ok, so you might say you'll never place arguments between redirects (although it would be a exception to what you said you allow). What if the file contained the line:

C:\Program Files\Application Name\bin\app.exe ola c:\file1 ole c:\file
+2
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Should the above return:
C:\Progra~1\Applic~1\bin\appexe~1 c:\file1o~1 c:\file2
or
C:\Progra~1\Applic~1\bin\app.exe ola c:\file1o~1 c:\file2
or
C:\Progra~1\Applic~1\bin\app.exe ola c:\file1 ole c:\file2
Probably not the first, but there's no way to know between the bottom two. It depends on what app.exe expects.

That's why I recommended you quote your paths:

sub quote   { local $_=$_[0]; s/(["\\])/\\$1/g; qq{"$_"} }
sub unquote { local $_=$_[0]; s/^"(.*)"$/$1/ or return $_; s/\\(.)/$1/
+g; $_ }

while (<IN>)
{
   @items = /("(?:[^"\\]|\\.)+"|[^"\s]+)/g;
   foreach (@items) {
      $_ = unquote($_);
      print(Win32::GetShortPathName($_) || quote($_), ' ');
   }

   print("\n");
}
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But that's not all! What the file doesn't exist? It's impossible to get the short file name of a file that doesn't yet exist!

Yes, I get your point now. I'm suppose that cmd.exe must be making some kind of assumptions in how it wants to interpet the lines. I'm guesing that I have to either quote things or go back to shortnames (or both I suspect). Thanks for your help

If you're looking to parse a path into directories and the filename, use File::Basename or File::Spec. If you're just creating a path for the output (log) file, though, I'm not sure why you need the short format in the first place. You should be able to use long (complete) directory and file names on windows - it works for me.

Update: I just realized your question might be refering to parsing the command line, not just the filenames. If that's the case you'll have to look at @ARGV (see perlvar), which contains command line arguments. You might also want to consider using something like Getopt rather than pulling things out of @ARGV yourself.

Sorry, I wasn't clear. I'm not trying to pull apart a file name into directories and basenames - just loop through a file, take each line with Win32 filenames and convert the long names into short names. The new line will be passed to another application that can't deal with spaces in names

You say the first file name can be "followed by three other filenames". How can you tell where the file names end? Is a b c d 4 file names, or 3 (say 'a', 'b' and 'c d')? Windows and/or many applications support using double quotes to surround arguemnts with spaces in them.

>perl -MWin32 -e "print(Win32::GetShortPathName($_), ' ') foreach (@AR
+GV);" "My Documents" "Start Menu"
MYDOCU~1 STARTM~1
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If you want to implement double quoteing yourself...

sub deslash { local $_=$_[0]; s/\\(.)/$1/g; $_ }
s/"((?:[^"\\]|\\.)+)"/ deslash($1) /ge;
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Ahh - I think I understand the question now (in the future, a few lines of the input file to serve as an example would be helpful). If I am getting this right, you need to read in the input file line-by-line, examine the line for path/filenames, and convert those filenames to short format. What have you tried? It seems fairly straightforward - perhaps split on whitespace and/or a regex to identify the path/filenames on each line. (It is hard to construct a good regex without knowing the format of the lines, so posting that will help.)

(see update 2)