≡ Menu

reboot command

How To Upgrade CentOS Linux To Version 5.2

CentOS Linux 5.2 has been released and available for immediate update via yum command or
the i386 and x86_64 Architectures. From the announcement page:

CentOS-5.2 is based on the upstream release EL 5.2.0, and includes packages from all variants including Server and Client. All upstream repositories have been combined into one, to make it easier for end users to work with. And the option to further enable external repositories at install time is now available in the installer.

How do I update from CentOS-5.0 and 5.1 to 5.2?

Simply type the following command as root user:
# yum update
OR
# yum upgrade
Sample output:

......
....
shadow-utils-4.0.17-13.el 100% |=========================|  50 kB    00:00
---> Package shadow-utils.i386 2:4.0.17-13.el5 set to be updated
---> Downloading header for cups to pack into transaction set.
cups-1.2.4-11.18.el5_2.1. 100% |=========================| 165 kB    00:00
Transaction Summary
=============================================================================
Install      8 Package(s)
Update     191 Package(s)
Remove       2 Package(s)
Total download size: 298 M
Is this ok [y/N]: y

Finally, reboot your computer, enter:
# reboot

Ubuntu Linux today pushed out a new version of Linux kernel to fix serval local and remote security issues. A malicious CIFS server could cause a client system crash or possibly execute arbitrary code with kernel privileges. On SMP systems, a race condition existed in fcntl(). Local attackers could perform malicious locks, causing system crashes and leading to a denial of service. This security issue affects the following Ubuntu, Kubuntu, Edubuntu, and Xubuntu. releases:

=> Ubuntu 6.06 LTS
=> Ubuntu 7.04
=> Ubuntu 7.10

To fix this issue type the following two commands:
$ sudo apt-get update
$ sudo apt-get upgrade

You need to reboot your computer to effect the necessary changes, enter:
$ sudo reboot

RHEL 5.1 has been released. Redhat announced the availability of Red Hat Enterprise Linux 5.1, with integrated virtualization. This release provides the most compelling platform for customers and software developers ever, with its industry-leading virtualization capabilities complementing Red Hat's newly announced Linux Automation strategy. It offers the industry’s broadest deployment ecosystem, covering standalone systems, virtualized systems, appliances and web-scale "cloud" computing environments.

Besides supporting Linux virtual machines, RHEL 5.1 will also support Windows XP, Windows 2000, Windows Server 2003 and the forthcoming Windows 2008, Crenshaw said. RHEL 5.1 uses Xen for its virtualization.

How do I upgrade to RHEL 5.1?

Login as the root user and simply type the command to fetch all updates via RHN:
# yum update
Depend upon your network condition and software configuration it may take anywhere between 5-20 minutes. Once completed, just reboot the server:
# reboot
Verify that everything is working fine:
# netstat -tulpn
# netstat -nat
# tail -f /var/log/messages
# egrep -i 'error|warn' /var/log/messages
# egrep -i 'error|warn' /path/to/apps/log

Community driven enterprise CentOS Linux users should expect update soon too. You can apply above commends to upgrade your CentOS box.

How to: OpenBSD reset root password

If you forgot your root password, you can simply reset it. The general procedure for resetting password is as follows (if you are a Linux user, see how to reset Linux root password):

a) At boot> prompt force openbsd to boot into a single user mode

b) Next mount file system in read-write mode

c) Run passwd command

d) Sync file system

e) Reboot and login normally.

Procedure to reset root password

At boot> prompt type boot -s to boot into single user mode:
boot> boot -s
Next you will see a message as follows:

Enter pathname of shell or RETURN for sh:

Just hit [Enter] key to load sh shell.
Next mount / and /usr file system in read-write mode:
# mount -uw /
# mount /usr

Finally set or change the password for root user, enter:
# passwd
Press CTRL+D to boot into multiuser mode or just reboot server:
# reboot

Further reading

FreeBSD Reset or Recover Root Password

With FreeBSD version 5.4 and above the booting procedure is slightly changed. The older version of FreeBSD uses the boot -s option at Ok prompt. However, with FreeBSD version FreeBSD 5.4+ you don't have to type any commands. Here is the procedure to boot FreeBSD into a single user mode to reset root password.
[click to continue…]

Howto: Shutdown Linux Box Automatically

You may wonder - why should I shutdown the Linux box automatically? It depends upon your situation. For example, you are downloading couple of tar balls and you want to go home early. You can schedule a job to shutdown Linux after downloading is completed. Linux/UNIX/BSD/OS X comes with at and cron commands to automate task. Almost all common task can be automated using at command.
[click to continue…]