terminal - List of ANSI color escape sequences - Stack Overflow

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The ANSI escape sequences you're looking for are the Select Graphic Rendition subset. All of these have the form

\033[XXXm
where XXX is a series of semicolon-separated parameters.

To say, make text red, bold, and underlined (we'll discuss many other options below) in C you might write:

printf("\033[31;1;4mHello\033[0m");