showrgb

showrgb [filename]

filename
    Name of the file containing the color database to read. If no filename is specified, showrgb reads from standard input.

The showrgb command reads a color name database from standard input or a specified file and outputs the RGB values for the colors found. This is useful for determining the exact RGB representation of named colors which can then be used in various applications or configuration files. The command parses entries in the X color database format. It searches for color names and their corresponding RGB values, printing the results to standard output. showrgb can be helpful when needing precise color definitions for graphical applications or web development. It's a simple utility for inspecting color definitions.

showrgb only understands the X color database format. Other color database formats will not be parsed correctly. It may display unexpected results or errors if the input file is malformed. The command provides a simple display of color names and their RGB values, but doesn't offer advanced color manipulation or conversions.

The color database file should be formatted as a series of lines, each containing a color name followed by its RGB values, typically as integers. For example:
Red 255 0 0
Green 0 255 0
Blue 0 0 255

To display the RGB values from the standard X11 color database:
showrgb /usr/share/X11/rgb.txt

To pipe the contents of a custom color file to showrgb:
cat mycolors.txt | showrgb

showrgb is a legacy utility, primarily used in the context of X Window System development and configuration. Its origins trace back to the early days of graphical computing, when color definitions were crucial for achieving consistent appearance across different displays. Its purpose was simple - to quickly expose the RGB values of named colors within the X color database.

xcolors(5)