ls命令在linux等系统很常见,它的帮助信息如下所示

Usage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuSUX nor --sort.

-a, --all                  do not hide entries starting with .
-A, --almost-all           do not list implied . and ..
-b, --escape               print octal escapes for nongraphic characters
    --block-size=SIZE      use SIZE-byte blocks
-B, --ignore-backups       do not list implied entries ending with ~
-c                         with -lt: sort by, and show, ctime (time of last
                           modification of file status information)
                           with -l: show ctime and sort by name
                           otherwise: sort by ctime
-C                         list entries by columns

创建Options

// create the command line parser
CommandLineParser parser = new DefaultParser();

// create the Options
Options options = new Options();
options.addOption( "a", "all", false, "do not hide entries starting with ." );
options.addOption( "A", "almost-all", false, "do not list implied . and .." );
options.addOption( "b", "escape", false, "print octal escapes for nongraphic "
                                         + "characters" );
options.addOption( OptionBuilder.withLongOpt( "block-size" )
                                .withDescription( "use SIZE-byte blocks" )
                                .hasArg()
                                .withArgName("SIZE")
                                .create() );
options.addOption( "B", "ignore-backups", false, "do not list implied entried "
                                                 + "ending with ~");
options.addOption( "c", false, "with -lt: sort by, and show, ctime (time of last " 
                               + "modification of file status information) with "
                               + "-l:show ctime and sort by name otherwise: sort "
                               + "by ctime" );
options.addOption( "C", false, "list entries by columns" );

String[] args = new String[]{ "--block-size=10" };

try {
    // parse the command line arguments
    CommandLine line = parser.parse( options, args );

    // validate that block-size has been set
    if( line.hasOption( "block-size" ) ) {
        // print the value of block-size
        System.out.println( line.getOptionValue( "block-size" ) );
    }
}
catch( ParseException exp ) {
    System.out.println( "Unexpected exception:" + exp.getMessage() );
}

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