Unix is an operating system, like Windows XP, but unlike Windows, there is less GUI here.
Its an open source operating system, which has given rise to several flavors of it, like:
- Solaris - developed by Sun Microsystems
- AIX - developed by IBM
- HP-UX - developed by Hewlett-Packard
- BSD/OS - developed by Wind River
- Linux - the most popular and fastest growing of all the Unix-like operating systems
One can access/login an Unix server via tools like Putty (most popular), mRemote etc. Googling will give you several options.
For accessing it, one need to have a login id created on it via Unix adminstrator, along-with a password.
For security purpose, you will be asked to change your password at first login.
Once logged in successfully, you will find yourself at a command prompt, in your home directory like below:
userid@servername /home/useridThis "userid@servername" combination, i.e. your custom prompt is detemined by a global variable named PS1.
You can change this variable to change your prompt. This can be changed by editing a file called as .profile via vi editor.
This file is executed when one logs into the system, so any variables set in will come into effect for the rest of the session, unless changed explicitly.
Hidden files can be listed using -a option of ls command, like via ls -latr:
u807735@vnxhamapcogd01 /home/u807735 => ls -latr total 424 drwx--x--x 2 u807735 staff 256 Mar 20 2012 Mail/ -rw-r--r-- 1 u807735 staff 11 Mar 20 2012 .mh_profile -rwx------ 1 u807735 staff 396 Apr 24 2012 .profile* -rw-r--r-- 1 u807735 staff 514 May 10 2012 datafile .....Here, the files with a leading dot are actually hidden files.
One can open it using vi editor and then edit it and save it.
=> vi .profileOne can control the access to files and directories w.r.t. read, write and execute permissions at owner, group and others level using chmod command.
Here is short description of these 3 levels:
|owner||Actual owner of file|
|group||Members of owner's group|
|others||Everyone else, i.e. other than above 2|
One very dangerous command in Unix is "rm -f", which removes things forcefully, without confirmation. Use it cautiously.