The "cat" command prints the contents of one or more files.
In fact, it is named "cat" as an abbreviation
for "concatenate". To print the files named "dog"
and "mouse" in succession, you could type either
If you print them with one command,
the contents are printed in sequence with nothing
How many lines are there in all the files
whose names begin with "b"? Find out, then type
"answer N" where N is the total number of lines.