Browsing all articles tagged with rhel

Jan

How to Use the alias Command

Rai

Linux

alias, bash, code, command, hack, Linux, rhel, shortcut, Tips, trick

Let us say you execute the command ‘ls –alh’ every time you need a long listing of files and directories. Now you want a shortcut to do this. Fortunately, you can do so by using the command alias.

The alias command is useful for creating shortcuts for long commands or for correcting typing mistakes.

To create a shortcut for ls, you can do this:

$ alias ls=”ls -alh”

Now, everytime you execute ls command, it will be run as if you are executing the whole ls –alh command. Be reminded that this will replace the existing ls command. You may use a different name for the new shortcut like so:

$ alias ll=”ls -alh”

However, once you exit the current terminal, the alias will not be saved. To make the alias permanent, you may edit the .bashrc file in user’s home directory:

$ vi ~rai/.bashrc

Then insert the alias command after the line that says #system wide functions and aliases. Save and exit.

That should do it!

Jan

VIM Trick: How to Comment Multiple Lines

Rai

Linux

comment, debian, fedora, Linux, number, rhel, special, suse, text editor, ubuntu, vi, vim

If you need to comment out lines of text inside VIM, you can try this trick:

(Enter command mode in VIM)
:40,105s/^/#/g

This will insert the # character at the beginning of each line starting from line number 40 to line number 105.

If you cannot see the line numbers, do this:

(Enter command mode in VIM)
:set number

To remove the lines:
:set nonumber

This is quite handy if you need to comment out lines of codes in a script.

Mar

NASA Uses Linux – A Lot!

Rai

Linux

fedora, Linux, nasa, redhat, rhel, servers, shuttle, space

Jack Aboutboul writes an insider’s scoop as he unravels the truth behind the urban myth about NASA using Fedora and RHEL for their mission-critical machines.

Jack writes:

Â There has been a long standing rumor regarding NASA running Fedora which all of us in the Fedora community have been always intrigued by. Is it true? What are they doing with it there? Why don’t they run RHEL. Fortunately enough, a couple of weeks ago, I got to experience NASA behind the scenes, first hand, and hang out with the coolest members of the Fedora community, and find out the answer to these questions and lots more.

Read more about his trip-to-die-for to NASA including the pictures here.

Jan

Howto: Install yum On RHEL 4

Rai

How-To's, Linux, Tips, Troubleshooting Tags

centos, Linux, package, repository, rhel, rpm, up2date, update, yum

There are more than a couple of ways of updating Red Hat Enterprise Linux (RHEL) packages on your machine. One is by using up2date, the default package updater of RHEL systems. Unlike Fedora and CentOS which uses yum, up2date requires you to be registered to Red Hat Network (RHN) to be able to download or update your packages from the RHN repository.

Now, what if you need to install a certain package that is not available in your current repository by up2date? Or what if the package in the repository wreaks havoc in your system? Maybe you should try using yum to install or update rpm packages.

But… but… but how can I install yum in my RHEL machine?, you may ask. It’s actually very simple.

I got this tip from Babar Haq’s Blog with a little modification since I am using RHEL 4.

1. Download yum by using wget

# wget http://linux.duke.edu/projects/yum/download/2.0/yum-2.0.8-1.noarch.rpm

2. Install the rpm

# rpm -ivh yum-2.0.8-1.noarch.rpm

3. Configure /etc/yum.conf to use compatible repository

[main]
cachedir=/var/cache/yum
debuglevel=2
logfile=/var/log/yum.log
pkgpolicy=newest
distroverpkg=redhat-release
tolerant=1
exactarch=1

[base]
name=CentOS-$releasever – Base
baseurl=http://mirror.centos.org/centos/4/os/i386/
gpgcheck=1

[updates]
name=Red Hat Linux $releasever – Updates
baseurl=http://mirror.centos.org/centos/4/updates/i386/
gpgcheck=1

4. Download and install the CentOS GPG Key

# wget http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-4

# rpm –import RPM-GPG-KEY-CentOS-4

5. Test yum to see if it works (I tested by running full update on my machine)

# yum update

*Note: This will update ALL installed packages in your machine. If you do not want to do this, cancel the process or skip this step.

If you reach step 5 without encountering any errors, it means that yum is successfully updating your machine with the latest versions available in the repo.