jruby(1)

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).

--copyright Prints the copyright notice.

--version Prints the version of Ruby interpreter.

-0[octal] (The digit ``zero''.) Specifies the input record separa

tor ($/) 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 speci

fied, 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 use

ful 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).

-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.

UNIX Apr 2, 2007 UNIX