# OTS Signs Command Center Documentation
OTS Signs Command Center is an open source digital signage solution. It supports all main media types and can be interfaced to other sources of data using CSV, Databases or RSS.
Keywords: digital signage, signage, narrow-casting, ots-signs, open source, agpl, documentation

# Shell Command

Use Shell Command to instruct the Display to execute a command outside of the OTS Signs Command Center environment, using the operating system shell.

> Add the Shell Command Widget to Layouts to execute external commands, such as ‘volume up’ for a Layout with an Audio Widget that is set to play, and ‘volume down’ when the Layout finishes.

## Overview

- The command is executed when a Layout/Playlist containing the Shell Command Widget plays at its scheduled time.
- Select a preconfigured stored command.
- Create a command string using the command builder to pass directly to the shell, further information can be found here.
- Enter a command string using free text.
- Global commands allow for compatible commands to work with all Player types.
- Android and Linux Players require root access to use Shell Commands.
- Enable launching created commands via Windows Command Line (cmd.exe)
- Run a command for a fixed period by setting a duration, for example where your command shows something on the screen for a time and cannot close itself.

> On ticking the Set a duration box and entering a time in seconds on the Advanced tab, options will be made available on the Configuration tab to instruct OTS Signs Command Center to terminate the command it started running.

> In most cases, commands that are run from a Layout / Playlist tend to be background commands which trigger something to happen like screen on/off or restart the device etc. In such cases, the Set a duration box can be left unticked.

> For commands that are executed on a specific date/time, such as ‘reboots’, ‘turn on/off’ on opening/closing times for example, then please see the Add Event in the Scheduling section and Send Command in the Displays section.

#### Next…

Command Functionality