..
1. In Linux and Unix when listing files in directory the .. or ../ represents the parent directory and ./ is the current directory. Below is an example of what the output of the ls command may look like and an example of the ./ and ../ at the top of the file listing.
# ls -laxo
total 59712
drwxr-xr-x 2 hope 4096 Jul
28 21:53 ./
drwxr-xr-x 12 hope 4096 Jul 23 05:36 ../
-rw-r--r-- 1 hope
3 Jul 2 06:02 addwordlog.txt
-rw-r--r-- 1 hope 301243 Jul 28 21:50
badips.txt
-rw-r--r-- 1 hope 164939 Jul 28 10:41 badmail.txt
-rw-r--r--
1 hope 69295 Jul 28 21:53 email.log
-rw-r--r-- 1 hope 21 Jul 28 21:44
feedback.log
-rw-r--r-- 1 hope 46836728 Jul 28 20:23 hijacklogs.txt
2. A .. can also be used in a command line or in a file path to go back one directory. For example, when using either the MS-DOS cd command or Linux and Unix cd command typing cd .. will go back one directory.
When typing a file path for a file on a webpage or also in the command line ../ moves back one directory. For example, ../../mypicture.gif points to the mypicture.gif located back two directories deep. In other words if you or the web page you were viewing was in the /dir1/dir2/dir3/ directory the mypicture.gif would be in the dir1 directory.