use File::Copy;

our $VERBOSE = 1; # turn this off if you don't need the verbose messag
+es

for my $file (@files) {
    if (-f "old/$file") {
        print "old/$file -> new/$file\n" if $VERBOSE;
        move("old/$file", "new/.") or die "move: old/$file: $!";
    }
}
[download]

Note that if this encounters an error, it'll stop in the middle. Maybe in your application it's more right to push the erring filename to a @failed array and then print them all, retry, whatever. I don't know; it's just something to think about.

Also, I've assumed "/" is a correct filepath separator and in most cases it is, but if you want to write really portable code you'll want to look into File::Spec.

Also, I've assumed "/" is a correct filepath separator and in most cases it is, but if you want to write really portable code you'll want to look into File::Spec.

That's not the complete picture, as non-Unix operating systems support POSIX syntax (i.e. Unix) besides their own native syntax. All operating systems that run perl support POSIX syntax, otherwise the perl build process wouldn't work. For a bizarre native syntax, have a look at VMS. There can be problems if you try and mix native and POSIX, though sometimes in Windows, you can get away with a mixture of slashes leaning both ways.

My advice is to either stick to native syntax, with File::Spec and friends, or use POSIX syntax throughout. Beware that a user supplied filename might contain native syntax elements.

For more on this, and portability in general, please refer to my talk slides - I have given this talk at several YAPCs.

--

Oh Lord, won’t you burn me a Knoppix CD ?
My friends all rate Windows, I must disagree.
Your powers of persuasion will set them all free,
So oh Lord, won’t you burn me a Knoppix CD ?
(Missquoting Janis Joplin)

#!/usr/bin/perl

use strict;
use File::Copy;

my @files = ('one.txt','two.txt','three.txt');
for my $file (@files) {
    if (-f "old/$file") {
        print "old/$file moved to new/$file\n" ;
        copy("old/$file", "new/.") or die "Error Coping /old/$file: $!
+";
    }
}
[download]

use File::Copy;

grep { (move("old/$_", "new/.") or warn "$_ => $!") if -f } @files;
[download]

If you're going to use dense loop constructs like this, 'map' is a slightly better choice than grep for expressing your intentions. Or probably even better:

do { some; series of; commands; which can use $_; } foreach @files;
[download]

But this is only if you have an aversion to newlines (which I can relate to), since this clearly the same as:

foreach (@files) {
  some;
  series of;
  commands;
  which can use $_;
}
[download]

Thinking of it, I myself would probably use do {...} foreach @list; as you suggest, because I find it more readable.
At first I found that particular use of grep intriguing. Then again, I wonder whether it was a good idea to add such a (potentially confusing) functionality to grep, since foreach works perfectly fine.