This command can be used to highlight attributes by changing the color of the text. If the attribute attrib is in use, the specified attribute/color modifier is also applied. If no modifier is given, the current one is deleted. See the chapter about string escapes (see String Escapes) for the syntax of the modifier.
Screen understands two pseudo-attributes,
stands for high-intensity foreground color and
high-intensity background color.
attrcolor b "R"
Change the color to bright red if bold text is to be printed.
attrcolor u "-u b"
Use blue text instead of underline.
attrcolor b ".I"
Use bright colors for bold text. Most terminal emulators do this already.
attrcolor i "+b"
Make bright colored text also bold.