Here is an example of using its with-command-line macro. The following code specifies a trivial class with a main method that does nothing but print out the values of its command line arguments.
(ns cmd-line-demo
(:gen-class)
(:use clojure.contrib.command-line))
(defn -main [& args]
(with-command-line args
"Command line demo"
[[foo "This is the description for foo" 1]
[bar "This is the description for bar" 2]
[boolean? b? "This is a boolean flag."]
remaining]
(println "foo: " foo)
(println "bar: " bar)
(println "boolean?: " boolean?)
(println "remaining: " remaining)))
Compile the class at the REPL:
user> (compile 'cmd-line-demo)
cmd-line-demo
Example usage
1) Executing with no command line arguments will cause the help info to be displayed. The help info can also be displayed with --help or -h flags. Note that the help info is automatically generated from your cmdspec.
$ java -classpath . cmd_line_demo
Command line demo
Options
--foo <arg> This is the description for foo [default 1]
--bar <arg> This is the description for bar [default 2]
--boolean, -b This is a boolean flag.
2) Unspecified arguments receive the default value as specified in the cmdspec binding. For example, bar has a default value of 2.
$ java -classpath . cmd_line_demo --foo "changed value"
foo: changed value
bar: 2
boolean?: nil
remaining: []
3) Boolean flags are denoted by the suffix “?” in the cmdspec. Note that the flag itself does not include the “?” as part of its name.
$ java -classpath . cmd_line_demo -boolean
foo: 1
bar: 2
boolean?: true
remaining: []
4) Also note that you may specify flag aliases by specifying multiple symbols in the cmdspec. I have done this with the boolean? and b? flags.
5) Finally, I’ve specified that remaining capture all remaining arguments without associated flags.
$ java -classpath . cmd_line_demo -foo test file1 file2 file3
foo: test
bar: 2
boolean?: nil
remaining: [file1 file2 file3]