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.
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.
DynaFabric is an SSH-based command dispatching and systems management framework, designed for easy implementation on existing networks. It allows you to configure SSH key based authentication and centrally dispatch commands, manage installed software, maintain services, and enforce policies across your systems. It is designed to be platform agnostic; support is being developed for FreeBSD, OpenBSD, NetBSD RHEL/CentOS, Ubuntu, Solaris 10, Solaris 11, and Illumos.
chrony is a client and server for the Network Time Protocol (NTP). This program keeps your computer's clock accurate. It was specially designed to support systems with intermittent Internet connections, but it also works well in permanently connected environments. It can also use hardware reference clocks, the system real-time clock, or manual input as time references.
The Advanced Bash Scripting Guide is both a reference and a tutorial on shell scripting. This comprehensive book, the equivalent of 1,032 print pages, covers almost every aspect of shell scripting. It contains 382 profusely commented illustrative examples, a number of tables, and a cross-linked index/glossary. Not just a shell scripting tutorial, this book also provides an introduction to basic programming techniques, such as sorting and recursion. Included scripts are the Game of Life, a Perquackey variant, a Morse code trainer, and an implementation of the Gronsfeld Cipher. This book is suited for both individual study and classroom use. It covers Bash, up to and including version 4.2. Note that users of miniaturized single-board computers running Linux, such as the Raspberry Pi and the Beagle Bone, would find this Guide useful for learning and running Bash scripts to explore and expand the capabilities of these small, but powerful machines.
Monit is a utility for managing and monitoring processes, programs, files, directories, and devices on a Unix system. It conducts automatic maintenance and repair and can execute meaningful causal actions in error situations. It can be used to monitor files, directories, and devices for changes, such as timestamps changes, checksum changes, or size changes. It is controlled via an easy to configure control file based on a free-format, token-oriented syntax. It logs to syslog or to its own log file and notifies users about error conditions via customizable alert messages. It can perform various TCP/IP network checks, protocol checks, and can utilize SSL for such checks. It provides an HTTP(S) interface for access.
sud (superuser daemon) permits a user to switch to root privileges and to use a suid program in a nosuid environment. It is based on a client/server model and on the ability to pass file descriptors between processes. sud permits you to choose your authentication method, and your effective credentials will be checked by using a Unix domain socket.