cat tells you to print out everything in the file commands

  cat is short for concatenate, which means to combine two files together.
  Since we only have one file, cat simply prints out the contents.
  
  Good work! You now know how to display your first file.
  
  Now, let's practice by displaying the files A, B, and C separately.
  
  Afterwards, let's combine multiple files together using cat.
  
  $ cat A B C
  
  NOTE: Don't type the $ dollar symbol. The $ dollar symbol means run
        the command as normal user. Just type 'cat A B C'.