You can use '*' to look for a string of characters
from one of the character classes. Suppose, for example,
we wanted a long string of either 'a' or 'b', followed
by 'x'. Then we could write
In this directory is a file named "table".
It has only one line. On that line, replace all the digits
followed by a comma with the letters "too big". For example,
"123,000" should become "too big,000".
Then rewrite the file and type "readY".