@Evgeny Shvarov  - you cannot use "!<cmd line>" from the Output window of Studio.  It is often very helpful to run a command from the context of a serverside Caché/InterSystems IRIS process which you can do via the Output Window with the above command, but not with "!":

!whoami
whoami - Error <SYNTAX>

Kill stream Set sc = ##class(%Studio.SourceControl.ISC).RunCmd("whoami",.stream,,1) w ! do stream.OutputToDevice() If 'sc { Write $System.Status.GetErrorText(sc) }
CMD: whoami
irisusr

Again, this is particularly useful when running server-side source control commands (if you need to debug or augment hooks)

This is great, thank you Evgeny!!  Here is another one that I use, often from the Output window in Studio in order to execute an OS-level command (I most frequently use this for p4 commands to interact with my Perforce server from my IRIS server).  IIRC, original credit goes to @Timothy Leavitt 

Kill stream Set sc = ##class(%Studio.SourceControl.ISC).RunCmd("<insert OS Command here>",.stream,,1) w ! do stream.OutputToDevice() If 'sc {​​​​​ Write $System.Status.GetErrorText(sc) }​​​​​

All - please note the new Practice Questions have been added to this post as an attachment, and that the opening up of the Beta Test has been announced:

https://community.intersystems.com/post/beta-test-intersystems-ccr-techn...

If anyone hasn't registered as a beta tester yet and would like to do so, please email certification@intersystems.com