What are display command in UNIX system?

Display command are used to display or view content of file. Some display commands are as follows:
    Commands                      What it will do
     cat [options] file              concatenate (list) a file
     echo [text string]            echo the text string to standard output(monitor)
     head [number] file        display the first 10 (or number of) lines of a file
     more (or less or pg) [options] file     page through a text file
     tail [options] file             display the last few lines (or parts) of a file