Question

I have a C file running on Linux. It prints some lines in red (failures) and some in green (passes). As you might expect, it uses escape codes in the printf statements as follows:

#define BLACK  "\033[22;30m"
#define GREEN  "\033[22;31m"

printf(GREEN "this will show up green" BLACK "\n");

If the BLACK at the end wasn’t there, the terminal text will continue to be green for everything. In case you didn’t catch it, that’s fine for a terminal window with a non-black background, but otherwise you’ll end up with black-on-black. Not good! Running the program has this problem, as does capturing the output in a text file and then viewing the file with "more" or "less".

Is there a code to restore defaults instead of specifying a color at the end of the printf statement? This needs to be in C, but I would be interested in reading about other approaches.

---

I updated my macros as follows (note 31 is for red):

#define RESET_COLOR "\e[m"
#define MAKE_GREEN "\e[32m"

printf(MAKE_GREEN "this will show up green" RESET_COLOR "\n");

I found the following links helpful in understanding how these codes work:

• http://www.phwinfo.com/forum/comp-unix-shell/450861-bash-shell-escapes-not-working-via-putty-ssh.html explains what these escape sequences do, and to use ncurses if portability is needed.

• http://www.linuxselfhelp.com/howtos/Bash-Prompt/Bash-Prompt-HOWTO-6.html

• ANSI codes shows even more escape sequences; It is useful to get the big picture

Answer 1

Try using:

#define RESETCOLOR "\033[0m"

That should reset it to the defaults.

More about these terminal codes can be found in ANSI escape code.