07-23-2009
Most common UNIX commands are written in C, which is converted from source code to executable code in several steps.
many source files(.c) ---compile---> many object files(.o) ---link---> one executable file
Compilation turns seperate .c files into machine code, stored in object files, usually .o. If anything in a.c calls a function in b.c, that will not be incorporated into a.o, the objects are all separate from each other. Because of this a third step is needed to join them all together: Linking. This resolves where everything the seperate object files needs comes from, be it other objects or external libraries, and writes it out in a form your computer can load and execute natively, the executable file.
So any changes in the source mean the respective object file needs to be recompiled, and any new object files mean the executable has to be relinked. Only the source code is human-readable.
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CMAP(5) File Formats Manual CMAP(5)
NAME
cmap - format of .cmap files (color maps)
DESCRIPTION
Color-map files define the mapping between eight-bit color numbers and red, green and blue intensities used for those numbers. They are
read by Magic as part of system startup, and also by the :load and :save commands in color-map windows. Color-map file names usually have
the form x.y.z.cmapn, where x is a class of technology files, y is a class of displays, z is a class of monitors, and n is a version number
(currently 1). The version number will change in the future if the formap of color-map files ever changes. Normally, x and y correspond to
the corresponding parts of a display styles file. For example, the color map file mos.7bit.std.cmap1 is used today for most nMOS and CMOS
technology files using displays that support at least seven bits of color per pixel and standard-phosphor monitors. It corresponds to the
display styles file mos.7bit.dstyle5.
Color-map files are stored in ASCII form, with each line containing four decimal integers separated by white space. The first three inte-
gers are red, green, and blue intensities, and the fourth field is a color number. For current displays the intensities must be integers
between 0 and 255. The color numbers must increase from line to line, and the last line must have a color number of 255. The red, green,
and blue intensities on the first line are used for all colors from 0 up to and including the color number on that line. For other lines,
the intensities on that line are used for all colors starting one color above the color number on the previous line and continuing up and
through the color number on the current line. For example, consider the color map below:
255 0 0 2
0 0 255 3
255 255 255 256
This color map indicates that colors 0, 1, and 2 are to be red, color 3 is to be blue, and all other colors are to be white.
SEE ALSO
magic(1), dstyle(5)
4th Berkeley Distribution CMAP(5)