sydbox is a ptrace-based sandbox implementation. It intercepts system calls, checks for allowed filesystem prefixes, and denies them when checks fail. It has basic support for disallowing network connections. It has basic support to sandbox execve calls. It is based in part on catbox and strace.
sydep is a tool for simple deployment over rsync. In combination GIT it is very powerful instrument. It provides three actions: init, push, and pull. init creates config files for sydep in the current directory. These are sydep.cfg, which contains connection details, and .sydepignore, which specifies files to ignore. push uploads files from the working directory to the server. pull downloads existing files from the server. It downloads only those files which are already in the working directory.
synaptiks is a KDE touchpad tool consisting of a system settings module for touchpad configuration and a tray application for touchpad management. The system settings module allows you to configure basic as well as advanced touchpad settings. The tray application can switch your touchpad on or off, either manually using a global shortcut, or automatically, if external mice are plugged or while the keyboard is active.
syncpasswd is an Expect script that synchronizes passwords via SSH on multiple platforms (Linux/BSD, OS X, and Solaris). It takes hostnames as a list of arguments and changes the specified user passwords on those hosts. It outputs results to stdout and logs to /var/log/syncpasswd.log (by default).
Synergy lets you easily share a single mouse and keyboard between multiple computers with different operating systems without special hardware. It's intended for users with multiple computers on their desk since each system uses its own monitor(s). Just move the mouse off the edge of a screen to move to another screen; keyboard and mouse input is then redirected to the other screen. Synergy also lets you cut and paste between systems and it makes screen savers activate/deactivate in concert.
Synspam uses Netfilter NFQUEUE to catch the source IP address of any machine connecting to your mail server, running multiple tests against it (RBL check, regexp on the reverse name, etc.) before forwarding the connection to the MTA. In order to have as few false positives as possible, a scoring system is used. If the source IP address is believed to be a spammer IP address, the connection can be dropped. There is a dry run mode if you just want to test it, which is the default.
syren is a CLI file downloader somewhat similar to wget and aria2c. It features support for HTTP, HTTPS, and FTP, resumable downloads, HTTP proxy support (including CONNECT mode for HTTPS), LISP scripting support, a small reusable downloader library, a small, reusable, and fast LISP interpreter library, predictable console output suitable for parsing by frontends, cookie support, easy changing of UserAgent and Referer fields, POST method support, and more.
Sysinit is a system-initialization scheme for use with Linux and a daemon-management scheme for use with runit or daemontools. It provides a common interface to all functionality, and uses envdirs instead of sourced shell scripts or custom configuration files. It does error handling, handles dependencies gracefully and simply, and handles runlevels.
sysklogd-sql is a port of the sysklogd daemon that can log data to a MySQL or PostgreSQL database running either on the same machine or a remote database server. The SQL configuration is done in the standard syslog.conf file for easy administration and configuration. Also included is a set of sample PHP scripts to query the data from the syslog database. In a large environment, you can set up a central logging server, or configure a secure syslog environment that will make it very difficult to tamper with the syslog data.