Socat is a relay for bidirectional data transfer between two independent data channels. Each of these data channels may be a file, pipe, device (terminal or modem, etc.), socket (Unix, IP4, IP6 - raw, UDP, TCP), SSL, a client for SOCKS4, or proxy CONNECT. It supports broadcasts and multicasts, abstract Unix sockets, Linux tun/tap, GNU readline, and PTYs. It provides forking, logging, and dumping and different modes for interprocess communication. Many options are available for tuning socat and its channels. Socat can be used, for example, as a TCP relay (one-shot or daemon), as a daemon-based socksifier, as a shell interface to Unix sockets, as an IP6 relay, or for redirecting TCP-oriented programs to a serial line.
Dar is a shell command that makes backup of a directory tree and files. Its features include splitting archives over several files, DVD, CD, ZIP, or floppies, compression, full or differential backups, strong encryption, proper saving and restoration of hard links, extended attributes, file forks, Door inodes, and sparse files, remote backup using pipes and external commands (such as ssh), and rearrangement of the "slices" of an existing archive. It can run commands between slices, before and after saving some defined files or directories (for a proper database backup, for example), and quickly retrieve individual files from differential and full backups. Several external GUIs exist as alternatives to its CLI interface, like kdar, DarGUI, SaraB, etc.
dvtm brings the concept of tiling window management, popularized by X11-window managers like dwm, to the console. As a console window manager, it tries to make it easy to work with multiple console based programs like vim, mutt, cmus, or irssi. dvtm is intended to be used where X11 isn't available or over SSH. In conjunction with dtach, it can be seen as a lightweight alternative to GNU screen.
grepcidr can be used to filter a list of IP addresses against one or more Classless Inter-Domain Routing (CIDR) specifications, or arbitrary networks specified by an address range. As with grep, there are options to invert matching and load patterns from a file. grepcidr is capable of comparing thousands or even millions of IPs to networks with little memory usage and in reasonable computation time. It has endless uses in network software, including mail filtering and processing, network security, log analysis, and many custom applications.
The libstatgrab library provides an easy-to-use interface for accessing system statistics and information. Available statistics include CPU, Load, Memory, Swap, Disk I/O, and Network I/O. It was developed to work on Linux, FreeBSD, and Solaris. The package also includes two tools: saidar provides a curses-based interface for viewing live system statistics, and statgrab is a sysctl-like interface to the statistics.
sdparm has a command line interface for getting and setting SCSI mode page fields. Fields can be referred to by an acronym or a numerical address. It has support for various SCSI transport and vendor-specific mode pages. It also decodes Vital Product Data (VPD) pages and can send some simple SCSI commands. sdparm was originally written for Linux with ports to FreeBSD, Solaris, Tru64, and Windows.
Userinfo is a console utility to display a variety of information about a local user. It uses loadable modules to perform different tasks, which separate the output with a field deliminator. Some may find it useful in shell scripts to gather information that might be tedious by other methods.