unzip -l backup.zip 
Archive:  backup.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
        1  2010-02-05 22:29   /home/user/a/a.txt
        1  2010-02-05 22:28   /home/user/b/b.txt
        1  2010-02-05 22:29   /home/user/c/c.txt
---------                     -------
        3                     3 files