deallocvt - deallocate unused virtual terminals
deallocvt [ N1 N2 ... ]
If given no argument, the program deallocvt deallocates kernel memory and data structures for all unused virtual terminals. If arguments Ni are given, only TTY’s /dev/ttyNi are deallocated. A virtual terminal is unused if it is not the foreground console, and no process has it open for reading or writing, and no text has been selected on its screen.