Command-line applications, also referred to as

`Console Applications <http://en.wikipedia.org/wiki/Console_application>`_,

are computer programs designed to be used from a text interface, such as a

`shell <http://en.wikipedia.org/wiki/Shell_(computing)>`_. Command-line

applications usually accept various inputs as arguments, often referred to as

parameters or sub-commands, as well as options, often referred to as flags or

switches.

Some popular command-line applications include:

* `Grep <http://en.wikipedia.org/wiki/Grep>`_ - A plain-text data search utility

* `curl <http://curl.haxx.se/>`_ - A tool for data transfer with URL syntax

* `httpie <https://github.com/jakubroztocil/httpie>`_ - A command line HTTP

client, a user-friendly cURL replacement

* `git <http://git-scm.com/>`_ - A distributed version control system

* `mercurial <http://mercurial.selenic.com/>`_ - A distributed version control

system primarily written in Python