The "*" character is also used in substitute commands,
but it has a different meaning. Here it means
"any number of repetitions of the previous character".
is any number of 'a' characters, and
is any number of either 'a' or 'b' characters.
looks for an 'a' followed by any number of 'b'
You can use '*' after anything, including for example
removes all the blanks after the letter 'a'. In this
directory there is a file 'text'. On the third line,
remove the blanks after the word 'the'. Then rewrite the