next up previous
Next: Bibliography Up: Tips, Tricks, and Tools Previous: Comparing Files with md5


Most programs follow the same paradigm for configuration. The effective configuration for a program is assembled by layering parameters from the following sources in order:
Default parameters
Stored within the program
System-wide parameters
Stored in a shared directory
User parameters
Stored in the user's directory
Invocation parameters
Specified at invocation
For example, Xdefaults are typically compiled into the program and augmented by specifications in /usr/lib/X11/app-defaults/, $HOME/.Xdefaults, and the command line. The default color of the xclock background is white; a line in /usr/lib/X11/app-defaults/XClock like
XClock*background: orange
shows no sense of aesthetics and could be overridden with a line in $HOME/.Xdefaults:
XClock*background: cornsilk.
You might use the following to remind yourself to go home at 9pm:
$echo "xclock -display :0 -geometry 500x500 -bg red" | at 9pm

Reece Kimball Hart