OpenSSH – Wikibooks, open books for an open world – The OpenSSH suite provides secure remote access and file transfer. Since its initial release, it has grown to become the most widely used implementation of the SSH protocol. During the first ten years of its existence, ssh has largely replaced older corresponding unencrypted tools and protocols. The OpenSSH client is included by default in most operating system distributions, including OS X, Linux, BSD and Solaris. Any day you use the Internet, you are using and relying on dozens if not hundreds of machines operated and maintained using OpenSSH. A survey in 2008 showed that of the SSH servers found running, just over 80% were OpenSSH.  OpenSSH was first released towards the end of 1999. It is the latest step in a very long and useful history of networked computing, remote access and telecommuting. This book is for fellow users of OpenSSH to help them save effort and time through using OpenSSH, and especially SFTP, where it makes sense to use it.
ssl-cert-check » Linux Shtuff – [...] Digital certificates have become an essential part of Internet commerce, and are widely used to verify the identity of clients and servers. All digital certificates contain an expiration date which most client and server applications will check before using the certificates contents. If a client or server application detects that a certificate has expired, one or more implementation specific actions (e.g., abort connection, check or update a revocation list, alert user, etc.) are typically performed.[...]
Modoboa – Mail hosting made simple – Modoboa is a mail hosting and management platform including a modern and simplified Web User Interface. It provides useful components such as an administration panel or a webmail. Modoboa is modular: use only the features you need and build a customized environment. Its goal is to become a standalone solution, no need to use heterogeneous software anymore! Modoboa is for everyone: administrators or end-users, it makes your life easier!
Largest small system emulator – This entry weighs in at a magical 4043 bytes (8086 nibbles, 28,301 bits). It manages to implement most of the hardware in a 1980’s era IBM-PC using a few hundred fewer bits than the total number of transistors used to implement the original 8086 CPU. If you are using OS X, the included sc-ioccc.terminal configuration file will correctly display console applications that use ANSI graphics. [ via http://braindead.tumblr.com/post/72245783959 ]
Portable Shell – Autoconf – When writing your own checks, there are some shell-script programming techniques you should avoid in order to make your code portable. The Bourne shell and upward-compatible shells like the Korn shell and Bash have evolved over the years, and many features added to the original System7 shell are now supported on all interesting porting targets.