dtrx intelligently extracts many different archive types. It will get the contents from tar, zip, rpm, deb, and cpio archives, as well as compressed files, with one simple command. It helps keep your filesystem sane by putting every archive's contents into a dedicated directory, and making sure the owner can read and write whatever's extracted. It can even recursively extract archives.
libpetey is a small scientific/numerical computation library. It includes the following components: templated sorting routines; templated binary tree classes; a templated linked-list class; routines for finding the k-least and k-greatest elements in an array; "supernewton", a powerful one-dimensional root-finding algorithm that combines bracketing with fast, superlinear convergence; a class for working with dates and times; a templated sparse matrix class; datasets (the beginnings of a data-representation paradigm that generalizes matrices, which is mostly useful for easy linear interpolation, especially generalized, n-dimensional linear interpolation); a function for easy parsing of command line options; and command-line utilities for sparse matrix multiplication and eigenvalue decomposition.
Binmay is a command line binary search and replace program. It allows one to specify a binary string (in hex) to search for and, optionally, a binary string to replace it with. One can mask both search and replace strings as one can mask an IP. It is handy for changing broken user SID/RIDs in ntuser.dat files after you move a profile from somewhere to somewhere else.
Trash Can is a recycle bin implementation for the command line. It is a set of scripts that can be run with ksh, bash, or zsh. It has commands for file removal, file restoration (to the original path), permanent deletion of particular files from the trash can, automatic purging of trash that is more than a certain number of days old, completely emptying the trash can, configuring trash can storage capacity, and displaying trash can disk usage. Trash is compressed to take up less room.