Apache Commons logo Apache Commons CLI

Apache Commons CLI

The Apache Commons CLI library provides an API for parsing command line options passed to programs. It's also able to print help messages detailing the options available for a command line tool.

Commons CLI supports different types of options:

  • POSIX like options, for example tar -zxvf foo.tar.gz
  • GNU like long options, for example du --human-readable --max-depth=1
  • Java like properties, for example java -Djava.awt.headless=true -Djava.net.useSystemProxies=true Foo
  • Short options with value attached, for example gcc -O2 foo.c
  • long options with single hyphen, for example ant -projecthelp

A typical help message displayed by Commons CLI looks like this:

usage: ls
 -A,--almost-all          do not list implied . and ..
 -a,--all                 do not hide entries starting with .
 -B,--ignore-backups      do not list implied entried ending with ~
 -b,--escape              print octal escapes for nongraphic characters
    --block-size <SIZE>   use SIZE-byte blocks
 -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

Check out the introduction page for a detailed presentation.


A full User's Guide is available as are various project reports.

The Javadoc API documents are available online:

The source repository can be browsed.


Download the latest version.
The release notes are also available.

For previous releases, see the Apache Archive.


The commons mailing lists act as the main support forum. The user list is suitable for most library usage queries. The dev list is intended for the development discussion. Please remember that the lists are shared between all commons components, so prefix your email subject by [cli].

Issues may be reported via the ASF JIRA.

CLI 2?

Commons CLI 1.0 was formed from the merger of ideas and code from three different libraries - Werken, Avalon and Optz. In dealing with the bugs and the feature requests a freshly designed and not backwards compatible CLI 2 was created in 2004, but never finished or released.

The current plan is to continue to maintain the 1.x line. The CLI2 work may be found in the Commons Sandbox.