Rename and number files in a directory - perl

Question

I'm trying to rename all tif files in a folder and number them from 1 to x. Ex. initial filenames "image-2.tif" and "image-3.tif" would be rename "file1.tif" and "file2.tif".
Here is my code:
my $dirname = "../folder";
opendir (DIR, $dirname) or die "cannot open directory $dirname";
my #files = grep /.tif/, readdir DIR;
closedir (DIR);
my $basename = "file";
my $count = 1;
my $new;
foreach (#files) {
$new = "${basename}${count}.tif";
print "rename $_ ${basename}${count}.tif\n";
rename $_, $new;
$count++;
}
Although all files are read correctly, they are just not renamed.

Answer 1

You need to use a good path for your rename() function when you get the files from a different one. The module File::Spec can help to get it:
use File::Spec;
my $dirname = "../folder";
my $abs_path = File::Spec->rel2abs($dirname);
And:
foreach (#files) {
$new = "${basename}${count}.tif";
print "rename $_ ${basename}${count}.tif\n";
rename File::Spec->catfile($abs_path, $_), File::Spec->catfile($abs_path, $new);
$count++;
}

Answer 2

I would suggest changing your line:
rename $_, $new;
...to something more like:
rename($_, $new) or warn "rename: $_: $new: $!\n";
...and you should be able to see why it isn't working -- since rename returns false upon failure (and $! will tell you why it failed).
Also, the target of your rename operation (in your case: $new) needs to include the directory component as well (otherwise, your attempting to move the files into the process's current working directory (probably not what you intended)).
Finally, I would suggest that, instead of hard-coding the value of $dirname to a relative path, you should accept it as a command line argument. This allows your script to be run from any $PWD. See #ARGV in the perlvar manpage and/or the builtin shift command.
Therefore, something like this:
my $dirname = shift; # Accept dirname as commandline argument
opendir (DIR, $dirname) or die "cannot open directory $dirname";
my #files = grep /\.tif$/, readdir DIR; # Escape regex meta-char (.) and anchor to end of string ($).
closedir (DIR);
my $basename = "file";
my $count = 1;
my $new;
foreach (#files) {
$new = "${dirname}/${basename}${count}.tif"; # Include dirname in target path
print "rename $_ $new\n";
rename($_, $new) or warn "rename: $_: $new: $!\n"; #warn when rename fails
$count++;
}

Answer 3

I finally found exactly what I was looking for. With the help of Tim Peoples's response. The simplest response would be:
my $dirname = "../folder";
opendir (DIR, $dirname) or die "cannot open directory $dirname";
my #files = grep /[.]tif\z/, readdir DIR; #corrected pattern based on Sinan Ünür's comment
closedir (DIR);
my $basename = "file";
my $count = 1;
my $new;
foreach (#files) {
$new = "${basename}${count}.tif";
print "rename $_ $new\n";
rename ("$dirname/$_", "$dirname/$new") or warn "rename: $_: $new: $!\n"; #directory name added to both the original file name and new file name. Thanks to Tim for helping me found this error using warn.
$count++;
}