Shasplit takes a large data block, splits it into smaller parts, and puts those parts into an SHA-based content-addressed store. Reassembling those parts is a trivial "cat" invocation. Repeating parts (e.g., from previous split operations) are stored only once, which allows efficient incremental backups of whole LVM snapshots via Rsync. Shasplit shows its strengths on encrypted block devices, but might be useful for non-encrypted data, too.
springclean is a command line tool for cleaning up log files. It can select files based on name (exact or regex), age, or a combination of both. You can preview changes, and confirm before running each action. For each action you can find how much disk space has been freed, compress, move to another directory or remove your files, and create an audit trail with syslog.
Xidel is a command line tool to download Web pages and extract data from them. It can download files over HTTP/S connections, follow redirections, links, or extracted values, and process local files. The data can be extracted using XPath 2.0, XQuery 1.0, and JSONiq expressions, CSS 3 selectors, and custom, pattern-matching templates that are like an annotated version of the processed page. The extracted values can then be exported as plain text/XML/HTML/JSON, or assigned to variables to be used in other extract expressions or be exported to the shell. There is also an online CGI service for testing.
s6-portable-utils is a set of tiny general Unix utilities, often performing well-known tasks such as cut and grep, but optimized for simplicity and small size. They were designed for embedded systems and other constrained environments, but work everywhere. Other sets of small utilities are usually system-specific; for instance, the (otherwise excellent) BusyBox project only works on Linux.
Kloxo is a lightweight and powerful Web hosting panel that has been in development since 2002. It was formerly known as LxAdmin. It allows for adding customers, resellers, and wholesale resellers with few clicks. Clustering functions are also built in, so you can expand and add servers whenever you need. Migrating customers between servers is easy and automatic, making it the most extensible panel to date. The services installed by default are Apache, BIND, MySQL, Pure-ftpd, Qmail, and Bogofilter. You can also switch between Apache and Lighttpd, BIND and djbdns, Bogofilter and Spamassassin. All configuration files are converted automatically in the process.