cat
cat
- read / write / concatenate tac
- prints the lines of a file in reverse order. each line remains the same, but the order of lines is inverted.
cat > file cat » file (any subsequenet lines are appended to the file, until CTRL-D is typed)
using cat interactively
echo
-e option, along with the following switches, is used to enable special character sequences,
such as the newline character or horizontal tab