Solutions

1.  The files with a slash after them are directories.  The rest are files.

2.  $ ls -l memo.  memo is the size shown in the fifth field, and it was last
     modified on the date shown in the sixth field.

3.  ls filea fileb filed


    cp fileb fileb.copy
    cp filec filec.copy
    ls -l

5.  more filea.copy

6.  cat memo
    more memo

    The output of the above two commands looks the same because memo
    fits on one page.  When you use cat and more on bigfile however,
    the more command pages bigfile whereas the cat command scrolls
    it off the screen.

7.  mv file.copy junk
    ls
    more junk
    mv fileb.copy junk
    more junk

    The contents of filea is gone for good.

9.  cp memo    This gives an error because cp needs two arguments.
