View command learning
cat: the first line displays the file contents
tac: From the beginning of the last line of the display
nl: display the number of rows
more: show the file contents page by page
less: the more similar, but you can flip forward
head: Look at the first few lines -n complex parameters such as: head -n 3 See head three rows
tail: see the countdown a few lines with the -n parameters such as: tail -n 3 View reciprocal three rows
od: read the contents of the file in binary square
