How to login and logout of AIX Operating System ?

Because AIX is designed as a multiuser system, a level of security is implemented to control access. Each user of the system has a user name and associated password (optional).

AIX Login and Logout:

When the system has started and is ready for a user to log in, the login prompt (typically the word login:) is presented on the screen. At that point the user should enter the supplied user ID. If the user ID requires a password, the system will prompt for the password in a similar manner. While the user is typing a password, it does not appear on the screen. When logged in, the user is presented with a prompt (normally a dollar sign) which is the shell's way of requesting a command.

To terminate the session the user may either enter the exit or logout command, or press the key combination <Ctrl-d> (holding down the Ctrl key while pressing the d key.) logout only works if you are in your login shell.

$ LOGIN: <username>
 $ <ctrl+d>, EXIT, LOGOUT

Creating or Changing Password:

The user password is the primary mechanism for ensuring security on an AIX system. All passwords are encrypted and cannot be decoded by other users. The passwd command is used to change the user password and is an example of a simple command which may be entered at the shell prompt.

The system will start the passwd process which will prompt the user for their old password first. To prevent users being locked out of the system through a simple typing error, the new password is entered twice. Only if the two entries match is the new password accepted. The old password is invalid thereafter. When the passwd process terminates the user is again presented with the prompt requesting another command.


Command Format:

The order and separation of the elements of a command are important. The command or process name must come first. Spaces are used by the shell as separators on the command line and should not be placed
within the command name.

The options should follow the command name, separated by a space, and preceded by a minus sign (-). Multiple options may be grouped immediately after a single minus sign or separated by spaces and each preceded by a minus sign.

Options are typically used to modify the operation of the process. The arguments follow the options, again separated by a space. The order of the arguments will depend on the command.

EX: $ ls -l, $ clear, $ banner, $ Date, $ Cal 3 2013 
$ WHO, $ WHOAMI, $ Who Am I, $ Mail <username> 

MAN Command

The man command will look in the on-line manual for information on the commands, subroutines and files with the name title. This information will be presented on the screen one page at a time for the user to browse. The information consists of:

      EX:  MAN ls

PURPOSE              The title and a one-line description of the command
SYNTAX                The syntax of the command
DESCRIPTION      Many pages of information about the function and usage of the command with examples
FLAGS                   Description of available options
FILES                     Any system files associated with the command
RELATED INFO.   The names of any related commands
BUGS             Any information about the behavior/performance of the command in unusual circumstances.

The man -k command shows the manual sections that contain any of the given keywords in their title. The output from the command begins with the name of a command and the section number in which the command appears.

To use the -k flag, a superuser must have typed catman -w to create the /usr/share/man/whatis file.

If you want to view the output from the command enable(1), then you can enter $ man enable to obtain the manual pages for the enable command. If the section number is omitted, the man command searches all the sections of the manual. To obtain further information about the various man sections enter man man. Note that the apropos command is equivalent to man -k.

AIX Documentation:

The growing influence of the World Wide Web has made the Web Browser a common element of our day-to-day work. For this reason, AIX V5.1 has replaced InfoExplorer with a Web-based documentation system. The traditional look of InfoExplorer is retained to a certain extent in this new Web-based version.

The IBM V5.1 softcopy documentation is loaded on a documentation server. Any other computer in the network with appropriate Web-browser software (for example, the Netscape Navigator) can then become a documentation client. When users on a client computer request an AIX document, the request is sent to the Web server on a documentation server which then sends back the requested item. When searches are performed, they are done on the server computer and the results are then sent back to the user on the client computer

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