Sorry to be on the simple side, but I've just recently entered the monastery and not shortly before just picked up my first book on perl. I am in something of a healthy discussion with a colleague of mine also new to perl. A need came up for a script to take all files within a directory that have a name of an 10.x.x.x ip address and copy the file with a name of the corresponding hostname. I know that perl's mantra is 'theres more than one way to do it' but his method seems to not take advantage of perl's traits and makes a lot of system calls: 
#!/usr/bin/perl -w
system("ls -1 10.* > hostfilelist");
open (LIST, "hostfilelist");
push(@entrys, <LIST>);
foreach my $entry (@entrys) {
open (CURRENT, "$entry");
my @contents = <CURRENT>;
 
@results = grep {/hostname/} @contents;
#print $results[0];
@outputname = split (/ / , $results[0]);
#print $outputname[1];
system("touch $outputname[1]");
open (OUTPUTFILE, ">$outputname[1]");
print OUTPUTFILE "@contents";
close (LIST);
close (CURRENT);
close (OUTPUTFILE);
unlink ("hostfilelist");
}

[download]
my version of the same process is as follows: 
#!/usr/bin/perl -w

use strict;

my @entrys;
my $entry;
my $host;

#to specify the directory, just uncomment the next line and put in the
#real path to the dir, then comment out, or erase the opendir line tha
+t
#references "."
#opendir DIR, "/path/to/dir/with/configs" or die "Cant open dir $!\n";
opendir DIR, "." or die "Cant open dir $!\n";
  @entrys = readdir DIR;
#uncomment the next line if you are specifying a differenet directory
#other than the pwd.
#chdir "/path/to/dir/with/configs" or die "Cant change directory $!\n"
+;
foreach my $entry (@entrys) {
  next if ( $entry !~ /^10/ );
  open CURRENT, $entry or die "Cant open file $entry $!\n";
  while (<CURRENT>) {
    $host = $_;
    if ( $host =~ /^hostname/ ) {
      $host =~ s/^hostname\s(.*)/$1/;
      chomp $host;
      open OUTPUTFILE, ">$host" or die "Cant create file $!\n";
      print OUTPUTFILE <CURRENT>;
      close OUTPUTFILE;
    }
  }
  close CURRENT;
}

[download]
he argues that my script is longer and takes more time and memory. i see his as making several system calls and multiple arrays. granted both work and neither would rock the processor, but i am really looking for some kind of justification that i am on the right path towards improving what skills i have and thinking about more than just "did it work?".

humbly, -c

In reply to A question of efficiency by c

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