POSNUMCON is a command-line (or console mode) program for converting between positional numeral systems written in C++. It is able to convert between any positional numeral system (e.g. decimal, octal, binary and hexadecimal) with base (radix) between 2-36 (there is the possibility for extension). It offers full support for big length, negative, and floating-point (fractional) numbers, saving calculation results to a text file. It is fully and easily customizable.
Bviplus is a console ncurses based binary file editor (hex editor) with Vim-like keys and features. It can quickly open/edit/save very large files (> 2GiB). It can perform regexp-like pattern searches in hex or ASCII windows. It features search highlighting, multiple undo/redo, a tabbed multiple file interface, visual selection, cut and paste (which works between files as well), blob coloring, and more. It can run external programs on selected data, supporting any program that reads stdin and writes stdout. It has few dependencies for easy portability.
bed is an adjustable data format binary editor. Data formats are ASCII, unsigned and signed integers, float, bit-flags, bit-fields, labels, EBCDIC, and time_t. Different sizes and byte orderings are possible. Data types can be used in structures. Other data formats, filters, and procedures can be defined in plugins. It features copy, paste, undo, redo, search, replace, marks, record/play, and context sensitive help. bed can be used to edit raw hard drives. Under Linux and FreeBSD it is even usable without the X Window System.
SearchBin is a fast commandline program for searching within binary files. It's a bit like grep for binaries. It offers wildcard matching and has three capabilities for searching: for bytes using hexidecimal, for a plain text string, and for a smaller binary file. Any discovered matches will print the found offsets (0-based).
BEYE (Binary EYE) is a portable advanced file viewer with a built-in editor for binary, hexadecimal, and disassembler modes. It contains a highlighting Java/AVR/i86-AMD64/ARM-XScale/PPC64 disassembler, full preview of MZ, NE, PE, LE, LX, DOS.SYS, NLM, ELF, a.out, arch, coff32, PharLap, and rdoff executable formats, a code guider, and many other features.