Executes a command in the Windows command shell. :connect server[\instance -l timeout -U user -P password - Connects to a ...

:!! []
  - Executes a command in the Windows command shell.
:connect server[\instance] [-l timeout] [-U user [-P password]]
  - Connects to a SQL Server instance.
:ed
  - Edits the current or last executed statement cache.
:error 
  - Redirects error output to a file, stderr, or stdout.
:exit
  - Quits sqlcmd immediately.
:exit()
  - Execute statement cache; quit with no return value.
:exit()
  - Execute the specified query; returns numeric result.
go []
  - Executes the statement cache (n times).
:help
  - Shows this list of commands.
:list
  - Prints the content of the statement cache.
:listvar
  - Lists the set sqlcmd scripting variables.
:on error [exit|ignore]
  - Action for batch or sqlcmd command errors.
:out |stderr|stdout
  - Redirects query output to a file, stderr, or stdout.
:perftrace |stderr|stdout
  - Redirects timing output to a file, stderr, or stdout.
:quit
  - Quits sqlcmd immediately.
:r 
  - Append file contents to the statement cache.
:reset
  - Discards the statement cache.
:serverlist
  - Lists local and SQL Servers on the network.
:setvar {variable}
  - Removes a sqlcmd scripting variable.
:setvar  
  - Sets a sqlcmd scripting variable.