Oct 1, 2008

Beginners guide to Hack UNIX Part-2

Things to do when you are in: Some of the commands that you may want to try follow below:

who is on (shows who is currently logged on the system.)
write name (name is the person you wish to chat with)
To exit chat mode try ctrl-D.
EOT=End of Transfer.
ls -a (list all files in current directory.)
du -a (checks amount of memory your files use;disk usage)
cd\name (name is the name of the sub-directory you choose)
cd\ (brings your home directory to current use)
cat name (name is a filename either a program or documentation your username has written)

Most Unix programs are written in the C language or Pascal since Unix is a programmers' environment.
One of the first things done on the system is print up or capture (in a buffer) the file containing all user names and accounts. This can be done by doing the following command:

cat /etc/passwd

If you are successful you will a list of all accounts on the system. It should look like this:

root:hvnsdcf:0:0:root dir:/:
joe:majdnfd:1:1:Joe Cool:/bin:/bin/joe
hal::1:2:Hal Smith:/bin:/bin/hal

The "root" line tells the following info :
login name=root
hvnsdcf = encrypted password
0 = user group number
0 = user number
root dir = name of user
/ = root directory

In the Joe login, the last part "/bin/joe " tells us which directory is his home directory (joe) is.
In the "hal" example the login name is followed by 2 colons, that means that there is no password needed to get in using his name.

Conclusion: I hope that this file will help other novice Unix hackers obtain access to the Unix/Xenix systems that they may find. There is still wide growth in the future of Unix, so I hope users will not abuse any systems (Unix or any others) that they may happen across on their journey across the electronic highways of America. There is much more to be learned about the Unix system that I have not covered.
I will try to cover them in few next post.