perl批量改文件后缀

如题，perl批量改文件后缀，将已有的统一格式的文件后缀，修改为新的统一的文件后缀。

#!/bin/perl
use 5.010;

print "Please input file suffix which U want to rename!\n";
chomp (my $suffix_old = <>); # 去除输入中的回车符
print "Please output file suffix which U want to rename!\n";
chomp (my $suffix_new = <>);

foreach my $file(glob "*.$suffix_old") {
  my $new_file = $file;
  $new_file =~ s/\.$suffix_old/.$suffix_new/gm;
  if (-e $new_file) {
    warn "Cannot rename $file to $new_file: $new_file exists\n";
  } elsif (rename $file => $new_file) {
  } else {
    warn "rename $file to $new_file failed:$!";
  }
}