Learning Ruby

Appendix A. Ruby Reference

Reference material on Ruby is gathered in this appendix for your convenience. You will find information about the following: interpreter options, reserved words (keywords), operators, escape characters, predefined variables, global constants, regular expressions, String unpack directives, Array pack directives, flags and fields for sprintf, file tests from Kernel#test, time formatting directives, RDoc options, and Rake options.

Ruby Interpreter

Here is the syntax for the Ruby interpreter:

ruby [switches] [--] [program filename] [arguments]

Switches (or command-line options) include:

−0[octal]

Specify record separator (\0 if no argument)

-a

Set autosplit mode with -n or -p (splits $_ into $F)

-c

Check syntax only

-Cdirectory

cd to directory before executing your script

-d

Set debugging flags (set $DEBUG to true)

-e 'command'

Execute one line of script; several -e’s allowed; omit [program filename]

-Fpattern

split( ) pattern for autosplit (-a)

-i[extension]

Edit ARGV files in place (make backup if extension is supplied)

-Idirectory

Specify $LOAD_PATH directory (may be used more than once)

-Kkcode

Specify KANJI (Japanese) code-set

-l

Enable line-ending processing

-n

Assume 'while gets( ); ... end' loop around your script

-p

Assume loop similar to -n but print line similar to sed

-rlibrary

Require the library, before executing your script

-s

Enable some switch parsing for switches after script name

-S

Look for the script using a PATH environment variable

-T[level]

Turn on tainting checks

-v

Print ...