|  | P copies its standard input, or the named files if given, to its
    standard output, stopping at the end of every 22nd line, and between
    files, to wait for a newline from the user. The option sets the
    number of lines on a page. 
    
    
    While waiting for a newline, p interprets the commands: !     Pass the rest of the line to the shell as a command.
 q     Quit.
 |