Archive for November, 2012

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

Checking For and Updating Packages

To see which installed packages on your system have updates available, use the following command:

yum check-update

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:

yum update package_name

Updating All Packages and Their Dependencies

To update all packages and their dependencies, simply enter yum update (without any arguments):

yum update

Unregistering a RHEL machine

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

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.


Consider a script that will take two command-line arguments and display them.

echo “The first variable is $1″
echo “The second variable is $2

« Prev