Ruby一般是在命令行中运行以下方式：
$ ruby [ options ] [.] [ programfile ] [ arguments ... ]
解释器可以调用任何下列选项来控制环境和行为的解释。
| 选项 | 描述 |
|---|---|
| -a | Used with -n or -p to split each line. Check -n and -p options. |
| -c | Checks syntax only, without executing program. |
| -C dir | Changes directory before executing (equivalent to -X). |
| -d | Enables debug mode (equivalent to -debug). |
| -F pat | Specifies pat as the default separator pattern ($;) used by split. |
| -e prog | Specifies prog as the program from the command line. Specify multiple -e options for multiline programs. |
| -h | Displays an overview of command-line options. |
| -i [ ext] | Overwrites the file contents with program output. The original file is saved with the extension ext. If ext isn't specified, the original file is deleted. |
| -I dir | Adds dir as the directory for loading libraries. |
| -K [ kcode] | Specifies the multibyte character set code (e or E for EUC (extended Unix code); s or S for SJIS (Shift-JIS); u or U for UTF-8; and a, A, n, or N for ASCII). |
| -l | Enables automatic line-end processing. Chops a newline from input lines and appends a newline to output lines. |
| -n | Places code within an input loop (as in while gets; ... end). |
| -0[ octal] | Sets default record separator ($/) as an octal. Defaults to if octal not specified. |
| -p | Places code within an input loop. Writes $_ for each iteration. |
| -r lib | Uses require to load lib as a library before executing. |
| -s | Interprets any arguments between the program name and filename arguments fitting the pattern -xxx as a switch and defines the corresponding variable. |
| -T [level] | Sets the level for tainting checks (1 if level not specified). |
| -v | Displays version and enables verbose mode |
| -w | Enables verbose mode. If programfile not specified, reads from STDIN. |
| -x [dir] | Strips text before #!ruby line. Changes directory to dir before executing if dir is specified. |
| -X dir | Changes directory before executing (equivalent to -C). |
| -y | Enables parser debug mode. |
| --copyright | Displays copyright notice. |
| --debug | Enables debug mode (equivalent to -d). |
| --help | Displays an overview of command-line options (equivalent to -h). |
| --version | Displays version. |
| --verbose | Enables verbose mode (equivalent to -v). Sets $VERBOSE to true |
| --yydebug | Enables parser debug mode (equivalent to -y). |
单字符命令行选项可以结合起来。下面两行表达同一个意思：
$ruby -ne 'print if /Ruby/' /usr/share/bin $ruby -n -e 'print if /Ruby/' /usr/share/bin
