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JRUBY(1) LOCAL 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 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).

−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

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