linux中五颜六色的文字

输出红色
\u001b[0;31mNot running\u001b[0m\n
输出绿色
\u001b[0;32mRunning [2640]\u001b[0m\n

why?

解释是这样的：

The original specification only had 8 colors, and just gave them names. The SGR parameters 30-37 selected the foreground color, while 40-47 selected the background. Quite a few terminals implemented "bold" (SGR code 1) as a brighter color rather than a different font, thus providing 8 additional foreground colors. Usually you could not get these as background colors, though sometimes inverse video (SGR code 7) would allow that. Examples: to get black letters on white background use ESC[30;47m, to get red use ESC[31m, to get bright red use ESC[31;1m. To reset colors to their defaults, use ESC[39;49m (not supported on some terminals), or reset all attributes with ESC[0m.
SGR code

大意是：“\u001b”是一个特殊的转意字符，遵从一定的规则，可以用来设置文字或背景颜色。

上面代码中，前面的\u001b[31m用于设定SGR颜色，后面的\u001b[0m相当于一个封闭标签作为前面SGR颜色的作用范围的结束点标记。

知道原因了
那就来了解一下 Linux终端常用的一些颜色码。字体颜色码有：重置=0，黑色=30，红色=31，绿色=32，黄色=33，蓝色=34，洋红=35，青色=36，白色=37；背景色有：黑色底=40，红色底=41，绿色底=42，黄色底=43，蓝色底=44，紫色底=45，天蓝底=46，白色底=47。