Maybe the simple solution is to make a copy the script and in the copy.

1. Comment out or delete any "use vars ..." lines.
2. edit out any "our" keywords.
3. Syntax check with "perl -wc copy.pl"

That ought to produce output somethng like:

P:\test>perl -wc junk.pl
Global symbol "$c" requires explicit package name at junk.pl line 8.
Global symbol "$rv" requires explicit package name at junk.pl line 9.
Global symbol "$c" requires explicit package name at junk.pl line 10.
Global symbol "$c" requires explicit package name at junk.pl line 11.
Global symbol "$c" requires explicit package name at junk.pl line 12.
Global symbol "$c" requires explicit package name at junk.pl line 12.
Global symbol "$c" requires explicit package name at junk.pl line 17.
Global symbol "$rv" requires explicit package name at junk.pl line 22.
Global symbol "$c" requires explicit package name at junk.pl line 22.
junk.pl had compilation errors.
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Is that the sort of information you are after?

There is also a module Devel::Something (Xref?) that produces a cross reference listing, but cpan appears to n down right now.

It's B::Xref and it's pretty cool.

X:\perl>perl -MO=Xref c:\perl\lib\strict.pm
File c:\perl\lib\strict.pm
  Subroutine (definitions)
    Package Internals
      &HvREHASH         s0
      &SvREADONLY       s0
      &SvREFCNT         s0
      &hash_seed        s0
      &hv_clear_placeholders  s0
      &rehash_seed      s0
    Package PerlIO
      &get_layers       s0
    Package Regexp
      &DESTROY          s0
    Package UNIVERSAL
      &VERSION          s0
      &can              s0
      &isa              s0
    Package Win32
      &BuildNumber      s0
      &CopyFile         s0
      &DomainName       s0
      &FormatMessage    s0
      &FsType           s0
      &GetCwd           s0
      &GetFullPathName  s0
      &GetLastError     s0
      &GetLongPathName  s0
      &GetNextAvailDrive  s0
      &GetOSVersion     s0
      &GetShortPathName  s0
      &GetTickCount     s0
      &IsWin95          s0
      &IsWinNT          s0
      &LoginName        s0
      &NodeName         s0
      &SetChildShowWindow  s0
      &SetCwd           s0
      &SetLastError     s0
      &Sleep            s0
      &Spawn            s0
  Subroutine (main)
    Package (lexical)
      $default_bits     i25
      %bitmask          i5
    Package strict
      $VERSION          3
      &bits             &25
c:\perl\lib\strict.pm syntax OK
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It's B::Xref and it's pretty cool.

There is also a Devel::Xref which I eventually pursuaded CPAN to allow me to download.

However, the documentation is less than clear (to me) on how to use it. I can get some output, but you have to embed it in the script, and the output is somewhat confusing.

Now you've pointed out B::Xref, and demonstrated how easy it is to use, I am way impressed. It is really cool. And fast!

I just tried it out on Date::Manip. Very interesting, if slightly scary reading.

Thanks for posting, I can see me using that a lot.

---

Examine what is said, not who speaks.

Silence betokens consent.

Love the truth but pardon error.

That is exactly what I've done, in the past. In fact, since such code is usually (in my experience) written without strict and without use vars (let alone our), simply turning on strict gives you the full scoop on global vars.

Run your program in the perl debugger. After it, you can print the values of assigned global variables with the |V debugger command. Note that this will print only those variables, that were used, so run the program first and break it after you think it's set all the global variables it uses, and invoke |V only after that. Also, you'll see lots of magic variables and other such junk in the output, which you should ignore.

Then, if you also want to know where those variables are accessed or changed, see Debugging with tied variables, or just grep for their names in the source code.

(Running with strict and seeing the errors is also a good idea, and is probably simpler, as someone else has recommended.)

It's actually really easy to write a B:: module to do this. I spent a few minutes on this:

package B::FindGlobals;

use B::Utils 'walkallops_filtered';

sub compile
{
    return sub {
        walkallops_filtered( \&gv_only, \&report_global );
    };
}

sub gv_only
{
    my $op = shift;
    return unless $op->name() =~ /^gv/;
    return unless $B::Utils::file eq $0;
    return 1;
}

sub report_global
{
    my $op = shift;
    printf "%s: % 4d %s\n", $B::Utils::file, $B::Utils::line,
        $op->gv()->NAME();
}

1;
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Install B::Utils, then run it on the file you want to check with perl -MO=FindGlobals filename.pl. You'll have to stuff this module somewhere in @INC under a B directory.

Question: Do you have to put the FindGlobals package in the B:: namespace for B::Utils to do its work?

Being right, does not endow the right to be rude; politeness costs nothing.
Being unknowing, is not the same as being stupid.
Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.

Not for B::Utils; that should work anywhere. You do have to put B::FindGlobals in an appropriate location for O to do its work though. That's the magic -MO=FindGlobals notation.

thomas