. Explain this sequence of commands:

$ mkdir empty

$ cd empty

$ cp a b

cp: cannot stat 'a': No such file or directory

$ cp a b >a $ # why is there no error message from cp this time? what is in file a ?

Explain this sequence of commands:

$ date >a $ cat a Wed Feb 8 03:01:21 EST 2012 $ cp a b $ cat b Wed Feb 8 03:01:21 EST 2012 $ cp a b >a $ cat b $ # why is file b empty? what is in file a ?

How many words are in each of these five output files?

$ echo one two three >out1 $ echo one two >out2 three $ echo one >out3 two three $ echo >out4 one two three $ >out5 echo one two three

What is in each file a, b, c, after this command line?

$ echo hi >a >b >c