---
name: "jruby"
section: "1"
platform: "linux"
package: "jruby"
version: "9.4.8.0+ds-3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/jruby"
---

# jruby(1)

Interpreted object-oriented scripting language

## NAME

**jruby** – Interpreted object-oriented scripting language

## SYNOPSIS

**jruby** \[**--copyright**\] \[**--version**\] \[**-Sacdlnpswvy**\] \[**-0**\[*octal*\]\] \[**-C** *directory*\] \[**-F** *pattern*\] \[**-I** *directory*\] \[**-K** *c*\] \[**-T**\[*level*\]\] \[**-e** *command*\] \[**-i**\[*extension*\]\] \[**-r** *library*\] \[**-x**\[*directory*\]\] \[**--**\] \[*program\_file*\] \[*argument* *...*\]

## DESCRIPTION

Jruby is a 100% pure-Java implementation of Ruby, 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.

## 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*

  Causes Ruby to switch to the directory.

- **-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.

- **-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**\[*level*\]

  Turns on taint checks at the specified level (default 1).

- **-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 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**

  - **--verbose**

  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 reserved word \_\_END\_\_. If the directory name is specified, Ruby will switch to that directory before executing script.

- **-y**

  - **--yydebug**

  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.