I am going to modify cat(1) to add an option to embolden and / or color symbols added by "--show-nonprinting", "--show-ends" and "--show-tabs". Maintainers, is this a change you would be willing to merge into Coreutils codebase? I ask because the manner & style I would use to write a patch intended for my own use would differ from that of a change intended for upstream, and I would like to avoid writing the patch twice if there was some hope of it being accepted.
The implementation I currently have in mind would work much like colorization in ls(1) and grep(1): a "--color" option would be added that could be set to "always", "never" (default) or "auto"; user-defined colors would be controlled by the "CAT_COLORS" environment variable containing escape sequences used to color symbols associated with each of the aforementioned command line flags; and when "CAT_COLORS" is unset, the default escape sequence used by all three options would be simply make the text bold. Using the same two-character convention used by GREP_COLORS and LS_COLORS, the default value of of "CAT_COLORS" would be "np=01:nl=01:tb=01"; "np" is short for "non-printing", "nl" is short for newline a la "--show-ends" and "tb" is short for "tab." I often find myself using xxd(1) after running "cat -A" to confirm some characters are what I think they are. With the proposed feature, it would be easier determine at a glance if certain characters are literal values that appear in the original data or if they were added by cat(1). Please let me know what you think, Eric
