.scn | command | .sdbBe care that .scn and .sdb are not for the files in the above expression.
.scn | command (| .sdb )then the command does not make outflow or not accept inflow.
If you execute some command with outflow, the command window may show strange characters. In this case and you are in xterm, push the middle button on your mouse with cntl key on the shell window. The popup menu appears and choose "Do full reset". Then the window is recovered. See manual page of the command xterm on your system.