If that's a concern, use File::Copy::move.

Hmmm, let's not, shall we? At least, not if you care about your permission bits.

$ touch /tmp/foo
$ chmod -w+x /tmp/foo
$ ls -l /tmp/foo
$ -r-x------ 1 javafan staff 0 Aug  7 18:16 /tmp/foo
$ perl -MFile::Copy -wE 'move "/tmp/foo", "/var/tmp/foo"'
$ ls -l /var/tmp/foo
$ -rw------- 1 javafan staff 0 Aug  7 18:16 /var/tmp/foo
[download]

But with mv:

$ touch /tmp/foo
$ chmod -w+x /tmp/foo
$ ls -l /tmp/foo
$ -r-x------ 1 javafan staff 0 Aug  7 18:18 /tmp/foo
$ mv /tmp/foo /var/tmp/foo
$ ls -l /var/tmp/foo
$ -r-x------ 1 javafan staff 0 Aug  7 18:18 /var/tmp/foo
[download]