开启转义功能
echo -e表示开启转义功能，比如：
彩色文字语法
echo -e "e[前景;背景;特效m""hello""e[0m"，例如：
console_codes
| 代码 | 含义 |
|---|---|
| 0 | reset all attributes to their defaults |
| 1 | set bold |
| 2 | set half-bright |
| 4 | set underscore |
| 5 | set blink |
| 7 | set reverse video |
| 10 | reset selected mapping, display control flag, and toggle meta flag |
| 11 | select null mapping, set display control flag, reset toggle meta flag |
| 12 | select null mapping, set display control flag, set toggle meta flag |
| 21 | set normal intensity |
| 22 | set normal intensity |
| 24 | underline off |
| 25 | blink off |
| 27 | reverse video off |
| 30 | set black foreground |
| 31 | set red foreground |
| 32 | set green foreground |
| 33 | set brown foreground |
| 34 | set blue foreground |
| 35 | set magenta foreground |
| 36 | set cyan foreground |
| 37 | set white foreground |
| 38 | set underscore on, set default foreground color |
| 39 | set underscore off, set default foreground color |
| 40 | set black background |
| 41 | set red background |
| 42 | set green background |
| 43 | set brown background |
| 44 | set blue background |
| 45 | set magenta background |
| 46 | set cyan background |
| 47 | set white background |
| 49 | set default background color |