+sub hash_cmd() {
+ my $len = length($file_hash);
+ my $cmd;
+
+ $len == 64 and return "openssl dgst -sha256";
+ $len == 32 and do {
+ my $cmd = which("md5sum") || which("md5") || die 'no md5 checksum program found, please install md5 or md5sum';
+ chomp $cmd;
+ return $cmd;
+ };
+ return undef;
+}
+
+my $hash_cmd = hash_cmd();