John the Ripper is a fast password cracker, currently available for many flavors of Unix, Windows, DOS, BeOS, and OpenVMS. Its primary purpose is to detect weak Unix passwords. It supports several crypt(3) password hash types commonly found on Unix systems, as well as Windows LM hashes. On top of this, lots of other hashes and ciphers are added in the community-enhanced version (-jumbo), and some are added in John the Ripper Pro.
dbf is an easy-to-use command line tool to show and convert the content of dBASE III, IV, and 5.0 files, as well as of FoxBase and Visual FoxPro. It reads xBASE-compatible databases and prints the content to the screen or converts it to comma-separated (*.csv) files which can be opened in Excel, StarOffice, and most other spread sheets. It can also be used to show some statistics about the content.
Steph is a portable C library for text mode windows, menus, dialogs, etc. The interface with the underlying system is provided by a separate library, so to port to a new system, only the interface library needs to be rewritten. Interface libraries are provided for Unix/Curses and IBM PC compatibles running DOS.
reversible hexdump is a hexdump/hex2bin-toolkit that dumps to a special readable and reversible hexadecimal byte-dump, where you can not only change bytes, but also insert or delete bytes. It has a flush-switch, where it will output hexbytes for each single char it reads. This is especially useful (imho) for watching output from slow devices (e.g., serial devices like mice). The hex2bin-utility (the reverse-hexdump) not only accepts hexbytes for input, but also double-quoted strings with most of the escape-chars known from C and makes good attempts at undumping even hexdumps with repetition-lines (a "*" on its own line). It's written in ANSI C.