use v5.36; use File::Copy; # Copy $path to $path.bak, preserving all earlier backups sub make_backup ($path ) { my $path_bak; if (-e $path) { $path_bak = _preserve_previous_backup($path); copy $path_bak, $path; } return $path_bak; # undef if path didn't exist sub _preserve_previous_backup ( $path ) { my $path_bak = "${path}.bak"; if (-e $path_bak) { _preserve_previous_backup($path_bak ); } move $path, $path_bak; return $path_bak; } }