Re^5: Debugger actions: On which lines?

It doesn't "fix the issue for me". Did you run the script under the debugger all the way?

Despite your results, using -w still turns warnings on globally, which is why the OP encountered the error with his code. See the demonstration below.

Of course none of this answers his original question, i.e. why is the action executed on every line after it's first executed?

[23:11][nick:~/monks]$ cat 1138950-2.pl
#!/usr/bin/perl -w

use strict;
use warnings;

my $x = 3;
my $y = 0;

for(1..3){
    $y = $x;
    $y++;
    $x -= $y;
}
[23:11][nick:~/monks]$ perl -d 1138950-2.pl

Loading DB routines from perl5db.pl version 1.49
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

main::(1138950-2.pl:6):    my $x = 3;
  DB<1> a 11 say $y                                                   
+                                                         
  DB<2> n                                                             
+                                                         
main::(1138950-2.pl:7):    my $y = 0;
  DB<2>                                                               
+                                                         
main::(1138950-2.pl:9):    for(1..3){
  DB<2>                                                               
+                                                         
main::(1138950-2.pl:10):        $y = $x;
  DB<2>                                                               
+                                                         
main::(1138950-2.pl:11):        $y++;
3
  DB<2>                                                               
+                                                         
main::(1138950-2.pl:12):        $x -= $y;
4
  DB<2>                                                               
+                                                         
main::(1138950-2.pl:10):        $y = $x;
4
  DB<2>                                                               
+                                                         
main::(1138950-2.pl:11):        $y++;
-1
  DB<2>                                                               
+                                                         
main::(1138950-2.pl:12):        $x -= $y;
0
  DB<2>                                                               
+                                                         
main::(1138950-2.pl:10):        $y = $x;
0
  DB<2>                                                               
+                                                         
main::(1138950-2.pl:11):        $y++;
-1
  DB<2>                                                               
+                                                         
main::(1138950-2.pl:12):        $x -= $y;
0
  DB<2>                                                               
+                                                         
Debugged program terminated.  Use q to quit or R to restart,
use o inhibit_exit to avoid stopping after program termination,
h q, h R or h o to get additional info.
Use of uninitialized value $y in say at (eval 18)[/Users/nick/perl5/pe
+rlbrew/perls/perl-5.22.0/lib/5.22.0/perl5db.pl:737] line 1.
 at (eval 18)[/Users/nick/perl5/perlbrew/perls/perl-5.22.0/lib/5.22.0/
+perl5db.pl:737] line 1.
    eval 'no strict; ($@, $!, $^E, $,, $/, $\\, $^W) = @DB::saved;pack
+age main; say $y;
' called at /Users/nick/perl5/perlbrew/perls/perl-5.22.0/lib/5.22.0/pe
+rl5db.pl line 737
    DB::eval called at /Users/nick/perl5/perlbrew/perls/perl-5.22.0/li
+b/5.22.0/perl5db.pl line 2681
    DB::DB called at /Users/nick/perl5/perlbrew/perls/perl-5.22.0/lib/
+5.22.0/perl5db.pl line 10345
    DB::fake::at_exit() called at /Users/nick/perl5/perlbrew/perls/per
+l-5.22.0/lib/5.22.0/perl5db.pl line 9916
    DB::END() called at (eval 18)[/Users/nick/perl5/perlbrew/perls/per
+l-5.22.0/lib/5.22.0/perl5db.pl:737] line 0
    eval {...} called at (eval 18)[/Users/nick/perl5/perlbrew/perls/pe
+rl-5.22.0/lib/5.22.0/perl5db.pl:737] line 0

  DB<2>
[download]

Compare with no -w switch:

[23:15][nick:~/monks]$ cat 1138950-3.pl
#!/usr/bin/perl

use strict;
use warnings;

my $x = 3;
my $y = 0;

for(1..3){
    $y = $x;
    $y++;
    $x -= $y;
}
[23:15][nick:~/monks]$ perl -d 1138950-3.pl

Loading DB routines from perl5db.pl version 1.49
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

main::(1138950-3.pl:6):    my $x = 3;
  DB<1> a 11 say $y                                                   
+                                                         
  DB<2> n                                                             
+                                                         
main::(1138950-3.pl:7):    my $y = 0;
  DB<2>                                                               
+                                                         
main::(1138950-3.pl:9):    for(1..3){
  DB<2>                                                               
+                                                         
main::(1138950-3.pl:10):        $y = $x;
  DB<2>                                                               
+                                                         
main::(1138950-3.pl:11):        $y++;
3
  DB<2>                                                               
+                                                         
main::(1138950-3.pl:12):        $x -= $y;
4
  DB<2>                                                               
+                                                         
main::(1138950-3.pl:10):        $y = $x;
4
  DB<2>                                                               
+                                                         
main::(1138950-3.pl:11):        $y++;
-1
  DB<2>                                                               
+                                                         
main::(1138950-3.pl:12):        $x -= $y;
0
  DB<2>                                                               
+                                                         
main::(1138950-3.pl:10):        $y = $x;
0
  DB<2>                                                               
+                                                         
main::(1138950-3.pl:11):        $y++;
-1
  DB<2>                                                               
+                                                         
main::(1138950-3.pl:12):        $x -= $y;
0
  DB<2>                                                               
+                                                         
Debugged program terminated.  Use q to quit or R to restart,
use o inhibit_exit to avoid stopping after program termination,
h q, h R or h o to get additional info.

  DB<2>                                                               
+                                                         
Use 'q' to quit or 'R' to restart.  'h q' for details.
[download]

The way forward always starts with a minimal test.

Comment on Re^5: Debugger actions: On which lines? Select or Download Code

Replies are listed 'Best First'.
Re^6: Debugger actions: On which lines? by james28909 (Deacon) on Aug 18, 2015 at 09:09 UTC
Maybe its the version of perl im using. Im also on windows. when I run perl -d script.pl I get a gui and I can step thru each line of code. I get no errors at all using the code I posted. I can remove the -w or the whole shebang and it makes no difference in -d or any other instance of it running.	[reply]
Re^7: Debugger actions: On which lines? by Laurent_R (Canon) on Aug 18, 2015 at 18:43 UTC
And what is the point of having this shebang line: `#!/usr/bin/perl -w` [download] or even more: `#!/usr/bin/perl` [download] under Windows? It makes very little sense...	[reply] [d/l] [select]
Re^8: Debugger actions: On which lines? by Your Mother (Archbishop) on Aug 18, 2015 at 19:53 UTC
At least three decent reasons in general: show intent, help other scripts/utilities with file type/content discovery, and portability.	[reply]
Re^9: Debugger actions: On which lines? by Laurent_R (Canon) on Aug 18, 2015 at 20:21 UTC
Re^10: Debugger actions: On which lines? by Your Mother (Archbishop) on Aug 18, 2015 at 21:00 UTC
Some notes below your chosen depth have not been shown here
Re^8: Debugger actions: On which lines? by james28909 (Deacon) on Aug 18, 2015 at 19:34 UTC
I never use the shebang unless i am in VM. I just copied code as is.	[reply]
Re^9: Debugger actions: On which lines? by Laurent_R (Canon) on Aug 18, 2015 at 19:53 UTC