Opposite Day: Reversing Lines In Files

The other day, my daughter said “it’s opposite day” when it was time to do a little homework, trying to get out of it! Which reminded me of a funny little command line tool called rev. Rev reads a file and reverses all the lines. So let’s touch a file called rev ~/Desktop/revtest and then populate it with the following lines: 123 321 123 Now run rev followed by the file name: rev ~/Desktop/revtest Now cat it: cat !$ Now rev it again: rev !$ You go go forward and back at will for fun, much more fun than homework… Enjoy!