Glossary

Last Updated: Wed 19 Jan, 2000

cat
A program on all unix systems designed to catenate any number of files together. The beauty of this program is that if you catenate from the standard input (keyboard) to standard output (the screen), then you have a really simply way of seeing which characters are generated for a given keypress

hexadecimal

Hexadecimal is a way of counting which makes more sense that decimal when dealing with computers. In hexadecimal, there are 16 digits, instead of the 10 we are used to. So when counting in hexadecimal, you get: 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10, 11... The reason why this is interesting when dealing with computers relates to the way the binary counting system works, but I won't go into that here.

Hexadecimal numbers are represented by prefixing them with 0x. ie: 0x15 = 16 + 5, or 21 in decimal.

od
The unix od program displays data in octal, or hexadecimal. This is very interesting if you want to see data which can't easily be displayed on the screen (binary data for example). See the man page for more details. (man od)

rxvt
rxvt is a color version of the popular X11 program: xterm. This provides the user with a command line interface while using a GUI. rxvt is generally seen as being the new and improved xterm, although the way it handles meta keys is nothing more than backward. Perhaps it will be improved in future versions.

xev

xev displays X11 events as they happen. Every mouse movement, every key press and release (even shift!) is reported to the user. If you type shift-a then you will see a sequence of events:

Thus you can see what X11 sends as an event when you press the Meta / Alt key, for example.


Stephen Riehm
e-mail: Stephen.Riehm@bigfoot.com

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