UNIX is an operating system which was first developed in the 1960s, and has been under constant development ever since. By operating system, we mean the suite of programs which make the computer work. It is a stable, multi-user, multi-tasking system for servers, desktops and laptops..
UNIX systems also have a graphical user interface (GUI) similar to Microsoft Windows which provides an easy to use environment.
There are many different versions of UNIX, although they share common similarities. The most popular varieties of UNIX are Sun Solaris, GNU/Linux, and MacOS X.
Everything in UNIX is either a file or a process.
A process is an executing program identified by a unique PID (process identifier).
A file is a collection of data. They are created by users using text editors, running compilers etc.
Examples of files:
When you first connect to a Unix system, you usually see a prompt such as the following −
Have your userid (user identification) and password ready. Contact your system administrator if you don't have these yet.
Type your userid at the login prompt, then press ENTER. Your userid is case-sensitive, so be sure you type it exactly as your system administrator has instructed.
Type your password at the password prompt, then press ENTER. Your password is also case-sensitive.
If you provide the correct userid and password, then you will be allowed to enter into the system. Read the information and messages that comes up on the screen, which is as follows.
login : test amrood's password: Last login: Fri Jan 25 10:4:32 2019 from 188.8.131.52 $
You will be provided with a command prompt (sometime called the $ prompt ) where you type all your commands.
All Unix systems require passwords to help ensure that your files and data remain your own and that the system itself is secure from hackers and crackers. Following are the steps to change your password −
Step 1 − To start, type password at the command prompt as shown below.
Step 2 − Enter your old password, the one you're currently using.
Step 3 − Type in your new password. Always keep your password complex enough so that nobody can guess it. But make sure, you remember it.
Step 4 − You must verify the password by typing it again.
$ passwd Changing password for test (current) Unix password:****** New UNIX password:******* Retype new UNIX password:******* passwd: all authentication tokens updated successfully $
Note − We have added asterisk (*) here just to show the location where you need to enter the current and new passwords otherwise at your system. It does not show you any character when you type.