--- name: "ruby1.9.1" section: "1" platform: "linux" package: "ruby1.9.1" version: "1.9.3.194-8.1+deb7u5" release: "Debian 7 (Wheezy)" platforms: ["linux"] url: "https://new.carta.tech/ruby1.9.1" --- # ruby1.9.1(1) Interpreted object-oriented scripting language ## NAME **ruby** – Interpreted object-oriented scripting language ## SYNOPSIS **ruby** \[**--copyright**\] \[**--version**\] \[**-SUacdlnpswvy**\] \[**-0**\[*octal*\]\] \[**-C** *directory*\] \[**-E** *external*\[:*internal*\]\] \[**-F** *pattern*\] \[**-I** *directory*\] \[**-K** *c*\] \[**-T**\[*level*\]\] \[**-W**\[*level*\]\] \[**-e** *command*\] \[**-i**\[*extension*\]\] \[**-r** *library*\] \[**-x**\[*directory*\]\] \[-{**enable**\|**disable**}-*FEATURE*\] \[**--dump**=*target*\] \[**--verbose**\] \[**--**\] \[*program\_file*\] \[*argument* *...*\] ## DESCRIPTION Ruby is an interpreted scripting language for quick and easy object-oriented programming. It has many features to process text files and to do system management tasks (as in Perl). It is simple, straight-forward, and extensible. If you want a language for easy object-oriented programming, or you don't like the Perl ugliness, or you do like the concept of LISP, but don't like too many parentheses, Ruby might be your language of choice. ## FEATURES Ruby's features are as follows: - **Interpretive** Ruby is an interpreted language, so you don't have to recompile programs written in Ruby to execute them. - **Variables have no type (dynamic typing)** Variables in Ruby can contain data of any type. You don't have to worry about variable typing. Consequently, it has a weaker compile time check. - **No declaration needed** You can use variables in your Ruby programs without any declarations. Variable names denote their scope - global, class, instance, or local. - **Simple syntax** Ruby has a simple syntax influenced slightly from Eiffel. - **No user-level memory management** Ruby has automatic memory management. Objects no longer referenced from anywhere are automatically collected by the garbage collector built into the interpreter. - **Everything is an object** Ruby is a purely object-oriented language, and was so since its creation. Even such basic data as integers are seen as objects. - **Class, inheritance, and methods** Being an object-oriented language, Ruby naturally has basic features like classes, inheritance, and methods. - **Singleton methods** Ruby has the ability to define methods for certain objects. For example, you can define a press-button action for certain widget by defining a singleton method for the button. Or, you can make up your own prototype based object system using singleton methods, if you want to. - **Mix-in by modules** Ruby intentionally does not have the multiple inheritance as it is a source of confusion. Instead, Ruby has the ability to share implementations across the inheritance tree. This is often called a ‘Mix-in’. - **Iterators** Ruby has iterators for loop abstraction. - **Closures** In Ruby, you can objectify the procedure. - **Text processing and regular expressions** Ruby has a bunch of text processing features like in Perl. - **M17N, character set independent** Ruby supports multilingualized programming. Easy to process texts written in many different natural languages and encoded in many different character encodings, without dependence on Unicode. - **Bignums** With built-in bignums, you can for example calculate factorial(400). - **Reflection and domain specific languages** Class is also an instance of the Class class. Definition of classes and methods is an expression just as 1+1 is. So your programs can even write and modify programs. Thus you can write your application in your own programming language on top of Ruby. - **Exception handling** As in Java(tm). - **Direct access to the OS** Ruby can use most UNIX system calls, often used in system programming. - **Dynamic loading** On most UNIX systems, you can load object files into the Ruby interpreter on-the-fly. - **Rich libraries** Libraries called "builtin libraries" and "standard libraries" are bundled with Ruby. And you can obtain more libraries via the package management system called \`RubyGems'. Moreover there are thousands of Ruby projects in Rubyforge (http://www.rubyforge.org) and RAA (http://raa.ruby-lang.org). ## OPTIONS Ruby interpreter accepts following command-line options (switches). They are quite similar to those of [perl(1)](/perl/1.md). - **--copyright** Prints the copyright notice. - **--version** Prints the version of Ruby interpreter. - **-0**\[*octal*\] (The digit “zero”.) Specifies the input record separator ($/) as an octal number. If no digit is given, the null character is taken as the separator. Other switches may follow the digits. **-00** turns Ruby into paragraph mode. **-0777** makes Ruby read whole file at once as a single string since there is no legal character with that value. - **-C** *directory* - **-X** *directory* Causes Ruby to switch to the directory. - **-E** *external*\[:*internal*\] - **--encoding** *external*\[:*internal*\] Specifies the default value(s) for external encodings and internal encoding. Values should be separated with colon (:). You can omit the one for internal encodings, then the value (Encoding.default\_internal) will be nil. - **-F** *pattern* Specifies input field separator ($;). - **-I** *directory* Used to tell Ruby where to load the library scripts. Directory path will be added to the load-path variable ($:). - **-K** *kcode* Specifies KANJI (Japanese) encoding. The default value for script encodings (\_\_ENCODING\_\_) and external encodings ( Encoding.default\_external) will be the specified one. *kcode* can be one of - **e** EUC-JP - **s** Windows-31J (CP932) - **u** UTF-8 - **n** ASCII-8BIT (BINARY) - **-S** Makes Ruby use the PATH environment variable to search for script, unless if its name begins with a slash. This is used to emulate #! on machines that don't support it, in the following manner: ``` #! /usr/local/bin/ruby # This line makes the next one a comment in Ruby \ exec /usr/local/bin/ruby -S $0 $* ``` - **-T**\[*level=1*\] Turns on taint checks at the specified level (default 1). - **-U** Sets the default value for internal encodings (Encoding.default\_internal) to UTF-8. - **-W**\[*level=2*\] Turns on verbose mode at the specified level, without printing version message at the beginning. The level can be; - **0** Verbose mode is "silence". It sets the $VERBOSE to nil. - **1** Verbose mode is "medium". It sets the $VERBOSE to false. - **2** **(default)** Verbose mode is "verbose". It sets the $VERBOSE to true.**-W** 2 is same as **-w** - **-a** Turns on auto-split mode when used with **-n** or **-p**. In auto-split mode, Ruby executes ``` $F = $_.split ``` at beginning of each loop. - **-c** Causes Ruby to check the syntax of the script and exit without executing. If there are no syntax errors, Ruby will print “Syntax OK” to the standard output. - **-d** - **--debug** Turns on debug mode. $DEBUG will be set to true. - **-e** *command* Specifies script from command-line while telling Ruby not to search the rest of the arguments for a script file name. - **-h** - **--help** Prints a summary of the options. - **-i** *extension* Specifies in-place-edit mode. The extension, if specified, is added to old file name to make a backup copy. For example: ``` % echo matz > /tmp/junk % cat /tmp/junk matz % ruby -p -i.bak -e '$_.upcase!' /tmp/junk % cat /tmp/junk MATZ % cat /tmp/junk.bak matz ``` - **-l** (The lowercase letter “ell”.) Enables automatic line-ending processing, which means to firstly set $\\ to the value of $/, and secondly chops every line read using chop!. - **-n** Causes Ruby to assume the following loop around your script, which makes it iterate over file name arguments somewhat like **sed** **-n** or **awk**. ``` while gets ... end ``` - **-p** Acts mostly same as -n switch, but print the value of variable $\_ at the each end of the loop. For example: ``` % echo matz | ruby -p -e '$_.tr! "a-z", "A-Z"' MATZ ``` - **-r** *library* Causes Ruby to load the library using require. It is useful when using **-n** or **-p**. - **-s** Enables some switch parsing for switches after script name but before any file name arguments (or before a **--**). Any switches found there are removed from ARGV and set the corresponding variable in the script. For example: ``` #! /usr/local/bin/ruby -s # prints "true" if invoked with `-xyz' switch. print "true\n" if $xyz ``` On some systems $0 does not always contain the full pathname, so you need the **-S** switch to tell Ruby to search for the script if necessary. To handle embedded spaces or such. A better construct than $\* would be ${1+"$@"}, but it does not work if the script is being interpreted by [csh(1)](/csh/1.md). - **-v** Enables verbose mode. Ruby will print its version at the beginning, and set the variable $VERBOSE to true. Some methods print extra messages if this variable is true. If this switch is given, and no other switches are present, Ruby quits after printing its version. - **-w** Enables verbose mode without printing version message at the beginning. It sets the $VERBOSE variable to true. - **-x**\[*directory*\] Tells Ruby that the script is embedded in a message. Leading garbage will be discarded until the first that starts with “#!” and contains the string, “ruby”. Any meaningful switches on that line will applied. The end of script must be specified with either EOF, ^D ( control-D), ^Z ( control-Z), or the reserved word \_\_END\_\_. If the directory name is specified, Ruby will switch to that directory before executing script. - **-y** - **--yydebug** DO NOT USE. Turns on compiler debug mode. Ruby will print a bunch of internal state messages during compiling scripts. You don't have to specify this switch, unless you are going to debug the Ruby interpreter. - **--disable-***FEATURE* - **--enable-***FEATURE* Disables (or enables) the specified*FEATURE* . - **--disable-gems** - **--enable-gems** Disables (or enables) RubyGems libraries. By default, Ruby will load the latest version of each installed gem. The Gem constant is true if RubyGems is enabled, false if otherwise. - **--disable-rubyopt** - **--enable-rubyopt** Ignores (or considers) the RUBYOPT environment variable. By default, Ruby considers the variable. - **--disable-all** - **--enable-all** Disables (or enables) all features. - **--dump**=*target* DO NOT USE. Prints the specified target. *target* can be one of; - **insns** disassembled instructions You don't have to specify this switch, unless you are going to debug the Ruby interpreter. - **--verbose** Enables verbose mode without printing version message at the beginning. It sets the $VERBOSE variable to true. If this switch is given, and no other switches are present, Ruby quits after printing its version. ## ENVIRONMENT - RUBYLIB A colon-separated list of directories that are added to Ruby's library load path ($:). Directories from this environment variable are searched before the standard load path is searched. e.g.: ``` RUBYLIB="$HOME/lib/ruby:$HOME/lib/rubyext" ``` - RUBYOPT Additional Ruby options. e.g. ``` RUBYOPT="-w -Ke" ``` Note that RUBYOPT can contain only **-d**, **-E**, **-I**, **-K**, **-r**, **-T**, **-U**, **-v**, **-w**, **-W,** **--debug**, **--disable-***FEATURE* and **--enable-***FEATURE*. - RUBYPATH A colon-separated list of directories that Ruby searches for Ruby programs when the **-S** flag is specified. This variable precedes the PATH environment variable. - RUBYSHELL The path to the system shell command. This environment variable is enabled for only mswin32, mingw32, and OS/2 platforms. If this variable is not defined, Ruby refers to COMSPEC. - PATH Ruby refers to the PATH environment variable on calling Kernel#system. - RUBYLIB\_PREFIX This variable is obsolete. And Ruby depends on some RubyGems related environment variables unless RubyGems is disabled. See the help of [gem(1)](/gem/1.md) as bellow. ``` % gem help ``` ## SEE ALSO - http://www.ruby-lang.org The official web site. - http://www.rubyforge.org hosting many open source ruby projects. - http://raa.ruby-lang.org Ruby Application Archive. ## REPORTING BUGS Security vulnerabilities should be reported via an email to⟨security@ruby-lang.org⟩. Reported problems will be published after they've been fixed. And you can report other bugs and feature requests via the Ruby Issue Tracking System (http://redmine.ruby-lang.org). Do not report security vulnerabilities via the system because it publishes the vulnerabilities immediately. ## AUTHORS Ruby is designed and implemented by Yukihiro Matsumoto ⟨matz@netlab.jp⟩. See \<**http://redmine.ruby-lang.org/wiki/ruby/Contributors**\> for contributors to Ruby.