plumb is a shell with focus on pipes: instead of pipelines, it can build large graphs of processes (nodes) and pipes (edges). Pipes are simple unidirectional streams without side effects. Traffic can be controlled by virtual processes (which are nodes just like real processes, but are implemented in plumb for minimal overhead). Virtual processes can split, merge, regex filter/alter, and shape the streams. Timers and starting/stopping processes or even rewiring the script on the fly are also supported. It is portable (using libporty) and behaves exactly the same way on Linux, Windows, Mac OS X, many BSD variants, and older UNIX systems.
Autojump is a tool that acts as a complement to cd: it makes navigating your filesystem a lot faster. It works by automagically maintaining a database of the directories you use the most from the command line, and allows you to jump back and forth between them, by typing just a few letters of the name of the directory you want to jump to. It works for Linux, Mac, and Cygwin under Windows.
The STX ExecPipe library provides a convenient C++ interface to execute child programs connected via pipes. It is a front-end to the system calls fork(), pipe(), select(), and execv() and hides all the complexity of these low-level functions. It allows a program to build a sequence of connected children programs with the input and output of the pipe sequence redirected to a file, string, or file descriptor. The library also allows custom asynchronous data processing classes to be inserted into the pipe or placed at the source or sink of the sequence.
File Commander is a text mode file manager and shell in the style of Norton Commander. It allows you to locate, copy, move, delete, view, edit, and execute your files. Its main display provides dual directory view panels which may be used to view a file list, a directory tree, or volume statistics. A command line is also provided and operates in conjuction with the directory panels to make it much more powerful than a regular CLI. Other features include built in support for archives, Unicode file name support, a built in viewer and editor with syntax highlighting, and Unicode text file support.