Xlsclients is a utility for listing information about the client applications running on a display. It may be used to generate scripts representing a snapshot of the user's current session.

-display displayname

This option specifies the X server to contact.

-a

This option indicates that clients on all screens should be listed. By default, only those clients on the default screen are listed.

-l

List in long format, giving the window name, icon name, and class hints in addition to the machine name and command string shown in the default format.

-m maxcmdlen

This option specifies the maximum number of characters in a command to print out. The default is 10000.

DISPLAY

To get the default host, display number, and screen.