rdoc documentation: usage(*args) Display usage information ... put something like this on top of your script: # == Synopsis # Blah blah blah. # ... method to display it def output_usage RDoc::usage('usa... bind it to the '-h' option via optionparser opts.on('-h', '--help') { output_help } ... source http://blog.toddwerth.com/entries/5

In Android.mk , you can define LOCAL_JARJAR_RULES like this: LOCAL_JARJAR_RULES := $(LOCAL_PATH)/jarjar-rules.t... and in jarjar-rules.txt define a rule like this: rule org.bouncycastle.** com.android.@0 The build will change all org.bouncycastle to com.android.org.bouncycastle . Therefore, in your classes which are dependent on the library produced, the import statements should look like: import com.android.org.bouncycastle... Help for the jarjar utility (in prebuilt/common/jarjar/ ): $ java -jar jarjar-1.0rc8.jar Jar Jar Links - ...

When you pass parameters from shell to Java, the list arguments may be messed up if there are spaces in the values. Start with a simple Java test class: public class EchoParams { public static voi... Tests: $ java EchoParams a b c Arg: a Arg: b Arg... Now wrap the command in a shell script ( echoparams.sh ): #!/bin/sh java EchoParams $* Tests: $ ./echoparams.sh a b c Arg: a Arg: b Arg... The quotes had no effect on the parameters list. Changing $* to $@ produces the same results. The correct way to quote the args list is: "$@" #!/bin/sh java EchoParams "$@" Test: $ ./echoparams.sh a b "c d" "1 2 3 4 5" Arg: a ...

There are two variables you can use while writing command line applications with PHP - $argc and $argv : $argc is the number of arguments plus one (the name of the script running). $argv is an array containing the arguments, starting with the script name as number zero ( $argv[0] ). Example: #!/usr/bin/php <?php var_dump($argv); ?>

The Unix shell passes these parameters to the shell script: Variable Meaning $* A single string representing all command line arguments separated by $IFS (internal field separator, usually a space) $@ A sequence of strings representing the command line arguments. $1,$2...$n $1 is the first argument, $2 is the second argument, and so on... $0 The name of the script itself. $# The number of arguments. Example shell script ( sharg.sh ): #!/bin/sh echo $# arguments passed to $0: $@ ... Output for ./sharg.sh "a b c d" : 1 arguments passed to ./sharg.sh: a b c d here ... Output for ./sharg.sh a "b c" d : 3 arguments passed to ./sharg.sh: a b c d here ...

It's quite easy for Perl to open a pipe and read from it: $file = "nospace.txt"; open(IN, "cat $file |") ... But the code breaks when the file name contains a space: # This does not work! $file = "yes space.txt"; ... On Windows, these don't work either: # This does not work! $file = "yes space.txt"; ... You need to use a technique called Safe Pipe Opens : $file = "yes space.txt"; $prog = "cat"; ...

Variable Meaning $_ The default or implicit variable. @_ Within a subroutine the array @_ contains the parameters passed to that subroutine. $a, $b Special package variables when using sort() $<digit> Contains the subpattern from the corresponding set of capturing parentheses from the last pattern match, not counting patterns matched in nested blocks that have been exited already. $. Current line number for the last filehandle accessed. $/ The input record separator, newline by default. $| If set to nonzero, forces a flush right away and after every write or print on the currently selected output channel. Default is 0 (regardless of whether the channel is really buffered by the system or not; $| tells you only whether you've asked Perl explicitly to flush after...

Command line arguments are passed to the python program in sys.argv , which is just a list. import sys for arg in sys.argv: prin...

Variables set automatically by shell: Variable Description $# Number of command-line arguments. $- Options currently in effect (arguments supplied to sh or to set). $? Exit value of last executed command. $$ Process number of current process. $! Process number of last background command. $0 First word; that is, command name. $n Individual arguments on command line (positional parameters). The Bourne shell allows only nine parameters to be referenced directly (n = 1-9); the Korn shell allows n to be greater than 9 if specified as ${n}. $* All arguments on command line ("$1 $2..."). $@ All arguments on command line, individually quoted ("$1" "$2" ...). Variables set automatically by Korn shell: Variable Description ERRNO Error number of last system call that failed. LINENO Current...

Using the alias command without arguments, or with the -p option prints out the list of aliases: [peaches@bashful ~]$ alias -p alias l.='ls -d .... Follow the examples above to define a new alias.