Checksums takes a file of predetermined MD5 checksums and compares with the current sum. It can be installed as a command line tool, or as a CGI which will allow you to upload the sums file remotely. In either case it is a useful tool to detect changes in your system files, such as a trojan.
You can download it from the following link: https://packetstormsecurity.com/files/download/10927/checksums-1.0.tar.gz
Source: https://packetstormsecurity.com/files/10927/checksums-1.0.tar.gz.html