$"=q;grep;;$,=q"grep";for(`find . -name ".saves*~"`){s;$/;;;/(.*-(\d+)-.*)$/;
$_=["ps -e -o pid | "," $2 | "," -v "," "];`@$_`?{print"+ $1"}:{print"- $1"}&&`r
m $1`;
print$\;}

##</code><code>##

$"=q;

grep;;$,=q"grep";

for(`find . -name ".saves*~"`){
  s;$/;;;
  /(.*-(\d+)-.*)$/;
  $_=["ps -e -o pid | "," $2 | "," -v "," "];
  `@$_` ? {print"+ $1"} : {print"- $1"} && `rm $1`;
  print $\;
}

##</code><code>##

 1:  $"=q;
 2:
 3:  grep;;$,=q"grep";
 4:
 5:  for(`find . -name ".saves*~"`){
 6:    s;$/;;;
 7:    /(.*-(\d+)-.*)$/;
 8:    $_=["ps -e -o pid | "," $2 | "," -v "," "];
 9:    `@$_` ? {print"+ $1"} : {print"- $1"} && `rm $1`;
10:    print $\;
11:  }

##</code><code>##

perl -e '@a = qw (a bc def); print "before: @a\n"; $"=q; print "after: @a\n";'

Output:
before: a bc def

##</code><code>##

perl -MO=Deparse -e '@a = qw (a bc def); print "before: @a\n"; $"=q; print
 "after: @a\n";'

Output:
@a = ('a', 'bc', 'def');          # ok, I agree
print "before: @a\n";             # yep, still with ya
$" = ' print "after: @a\\n"';     # whoa, this is unexpected
-e syntax OK                      # good news, I guess

##</code><code>##

$"=q;grep;;
$,=q"grep";

##</code><code>##

$" = 'grep';
$, = 'grep';

##</code><code>##

 1:  $"= 'grep' ;
 2:  $,= 'grep' ;
 3:
 4:  for(`find . -name ".saves*~"`){
 5:    s;$/;;;
 6:    /(.*-(\d+)-.*)$/;
 7:    $_=["ps -e -o pid | "," $2 | "," -v "," "];
 8:    `@$_` ? {print"+ $1"} : {print"- $1"} && `rm $1`;
 9:    print $\;
10:  }

##</code><code>##

     /               # start of pattern match
      (              # begin storing into $1
       .*            #    store any number of any character...
         -           #    ...followed by a hyphen...
          (          #    begin storing into $2
           \d        #       ...any digit...
            +        #       ...as many as we can grab...
          )          #    stop storing into $2
         -           #    ...followed by another hyphen
       .*            #    ...followed by any number of any character...
      )              # stop storing into $2
     $               # end of the line, bub
    /x;              # / to terminate regex, x to allow comments

##</code><code>##

@command = "ps -e -o pid | grep $2 | grep -v grep ";
$ar_command = \@command;

##</code><code>##

perl -e '$foo = 0; $foo==0 ? print "foo is zero" : print "foo is non-zero";'

Output:
foo is zero

##</code><code>##

$foo = 0;
if ( $foo == 0 ) {
  print "foo is zero" ;
} else {
  print "foo is non-zero" ;
}

##</code><code>##

if ( `@$_` ) {
  print "+ $1";
} else {
  print "- $1" && `rm $1`;
}

##</code><code>##

my $owner_is_still_running = `@$_`;             # search for a specific $pid
if ( $owner_is_still_running ) {
  print "$owner_is_still_running, keeping $1";  # found $pid, keep tempfile
} else {
  print "removing $1";                          # didn't find $pid
  `rm $1`;                                      # remove $pid's tempfile
}

##</code><code>##

#!/usr/bin/perl

use strict;
use warnings;
# find files that match the naming convention
my @files = `find . -name ".saves*~"`;

foreach ( @files ) {
   chomp;

   # hold onto filename, and extract creator's pid
   /                # start of pattern match
    (               # begin storing into $1
     .*             #    store any number of any character...
       -            #    ...followed by a hyphen...
        (           #    begin storing into $2
         \d         #       ...any digit...
          +         #       ...as many as we can grab...
        )           #    stop storing into $2
       -            #    ...followed by another hyphen
     .*             #    ...followed by any number of any character...
    )               # stop storing into $2
   $                # end of the line, bub
   /x;              # / to terminate regex, x to allow comments

   my ( $filename, $creator_pid ) = ( $1, $2 );

   # Check process stack for the creator's pid, storing command result
   my $command = "ps -e -o pid | grep $creator_pid | grep -v grep";
   my $command_result = `$command`;

   # if the command result is positive, leave $filename alone...
   # ... otherwise, remove $filename
   if ( $command_result ) {
      print "+ $filename\n";
   } else {
      print "- $filename\n";
      `rm $filename`;
   }
}