Applies to: 
SQL Server
The sqlagent application starts SQL Server Agent from the command prompt. Usually, SQL Server Agent should be run from SQL Server Management Studio or by using SQL-SMO methods in an application. Only run sqlagent from the command prompt when you're diagnosing SQL Server Agent, or when you're directed to it by your primary support provider.
Syntax
sqlagent
-c [ -v ] [ -i instance_name ]
Arguments
-c
Indicates that SQL Server Agent is running from the command prompt and is independent of the Microsoft Windows Services Control Manager. When -c is used, SQL Server Agent can't be controlled from either the Services application in Administrative Tools or SQL Server Configuration Manager. This argument is mandatory.
-v
Indicates that SQL Server Agent runs in verbose mode and writes diagnostic information to the command-prompt window. The diagnostic information is the same as the information written to the SQL Server Agent error log.
-i instance_name
Indicates that SQL Server Agent connects to the named SQL Server instance specified by instance_name.
Remarks
After it displays a copyright message, sqlagent displays output in the command prompt window only when the -v switch is specified. To stop sqlagent, press Ctrl+C at the command prompt. Don't close the command-prompt window before stopping sqlagent.