Command line utilities for managing users and groups
useradd, userm od, userdel > Standard utilities for adding, modifying, and deleting user accounts.
groupadd, groupmod,groupdel > Standard utilities for adding, modifying, and deleting groups.
gpasswd > Standard utility for administering the /etc/group configuration file.
pwck, grpck > Utilities that can be used for verification of the password, group,and associated shadow files.
pwconv, pwunconv > Utilities that can be used for the conversion of passwords to shadow passwords, or back from shadow passwords to standard passwords
Red Hat Enterprise Linux 6.3 Authentication
Support for central management of SSH keys.
Previously, it was not possible to centrally manage host and user SSH public keys. Red Hat Enterprise Linux 6.3 includes SSH public key management for Identity Management servers as a Technology Preview. OpenSSH on Identity Management clients is automatically configured to use public keys which are stored on the Identity Management server. SSH host and user identities can now be managed centrally in Identity Management.
Package: sssd-1.8.0-32
Checking For and Updating Packages
To see which installed packages on your system have updates available, use the following command:
Updating Packages
You can choose to update a single package, multiple packages, or all packages at once. If any dependencies of the package (or packages) you update have updates available themselves, then they are updated too.
Updating a Single Package
To update a single package, run the following command as root:
Updating All Packages and Their Dependencies
To update all packages and their dependencies, simply enter yum update (without any arguments):
Unregistering a RHEL machine
The only thing required to unregister a machine is to run the unregister command. This removes the system’s entry from the subscription service, unsubscribes it from any subscriptions, and, locally, deletes its identity and entitlement certificates.
In the Red Hat Subscription Manager GUI, there is an Unregister button in the top right corner of the window.
From the command line, this requires only the unregister command.
Unregistering a Consumer
[root@server1 ~]# subscription-manager unregister
Bash Command line Arguments
These are variables that contain the arguments to a script when it is run. These variables are accessed using $1, $2, … $n, where $1 is the first command-line argument, $2 the second, etc. Arguments are delimited by spaces. $0 is the name of the script. The variable $# will display the number of command-line arguments supplied; this number is limited to 9 arguments in the older shells, and is practically unlimited in the modern ones.
Example:
Consider a script that will take two command-line arguments and display them.
#!/bin/sh
echo “The first variable is $1″
echo “The second variable is $2
