Ruby - Command Line Options

Quiz

Ruby is generally run from the command line in the following way −

$ ruby [ options ] [.] [ programfile ] [ arguments ... ]

The interpreter can be invoked with any of the following options to control the environment and behavior of the interpreter.

Sr.No.	Option & Description
1	-a Used with -n or -p to split each line. Check -n and -p options.
2	-c Checks syntax only, without executing program.
3	-C dir Changes directory before executing (equivalent to -X).
4	-d Enables debug mode (equivalent to -debug).
5	-F pat Specifies pat as the default separator pattern ($;) used by split.
6	-e prog Specifies prog as the program from the command line. Specify multiple -e options for multiline programs.
7	-h Displays an overview of command-line options.
8	-i [ ext] Overwrites the file contents with program output. The original file is saved with the extension ext. If ext isn't specified, the original file is deleted.
9	-I dir Adds dir as the directory for loading libraries.
10	-K [ kcode] Specifies the multibyte character set code (e or E for EUC (extended Unix code); s or S for SJIS (Shift-JIS); u or U for UTF8; and a, A, n, or N for ASCII).
11	-l Enables automatic line-end processing. Chops a newline from input lines and appends a newline to output lines.
12	-n Places code within an input loop (as in while gets; ... end).
13	-0[ octal] Sets default record separator ($/) as an octal. Defaults to \0 if octal not specified.
14	-p Places code within an input loop. Writes $_ for each iteration.
15	-r lib Uses require to load lib as a library before executing.
16	-s Interprets any arguments between the program name and filename arguments fitting the pattern -xxx as a switch and defines the corresponding variable.
17	-T [level] Sets the level for tainting checks (1 if level not specified).
18	-v Displays version and enables verbose mode.
19	-w Enables verbose mode. If program file not specified, reads from STDIN.
20	-x [dir] Strips text before #!ruby line. Changes directory to dir before executing if dir is specified.
21	-X dir Changes directory before executing (equivalent to -C).
22	-y Enables parser debug mode.
23	--copyright Displays copyright notice.
24	--debug Enables debug mode (equivalent to -d).
25	--help Displays an overview of command-line options (equivalent to h).
26	--version Displays version.
27	--verbose Enables verbose mode (equivalent to -v). Sets $VERBOSE to true.
28	--yydebug Enables parser debug mode (equivalent to -y).

Single character command-line options can be combined. The following two lines express the same meaning −

$ruby -ne 'print if /Ruby/' /usr/share/bin
   
$ruby -n -e 'print if /Ruby/' /usr/share/bin

ruby_environment.htm

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