Tcl provides a portable scripting environment for Unix, Windows, and Macintosh that supports string processing and pattern matching, native file system access, shell-like control over other programs, TCP/IP networking, timers, and event-driven I/O. Tcl has traditional programming constructs like variables, loops, procedures, namespaces, error handling, script packages, and dynamic loading of DLLs. Tk provides portable GUIs on UNIX, Windows, and Macintosh. A powerful widget set and the concise scripting interface to Tk make it a breeze to develop sophisticated user interfaces.
Ghostscript is a processor for PostScript and PDF files. It can rasterize these files to a wide variety of printers, devices for screen preview, and image file formats. Since applications tend to prepare pages for printing in a high-level format such as PostScript, most Unix users with low-level bitmap printers, such as inkjets, use GhostScript as part of the printing process. In addition, Ghostscript is capable of converting PostScript files, functionality comparable to Adobe Acrobat Distiller, but on the command line. In addition, Ghostscript is used for file import and viewing by a great many other applications, including xv, ImageMagick, gimp, and xdvi. Several GUI wrappers for viewing PostScript and PDF files exist, including GSview, ghostview, gv, ggv, and kghostview. This is far from a comprehensive list.
The "Schily" Tool Box is a set of tools written or managed by Jörg Schilling. It includes programs like: cdrecord, cdda2wav, readcd, mkisofs, smake, bsh, btcflash, calc, calltree, change, compare, count, cpp (K&R original), devdump, hdump, isodebug, isodump, isoinfo, isovfy, label, mt, p, patch, sccs, scgcheck, scpio, sdd, sfind, sformat, smake, sh (Bourne Shell), star, star_sym, suntar, gnutar, tartest, termcap, and ved.