Unable to login to remote server via ssh
A funny thing happened to one of my Red Hat 5 Enterprise servers after applying the errata. I rebooted the servers as usual after applying the updates, and they came …
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How to create a new superuser in Linux
The administrative account ‘root’ is the most powerful user in Linux and Unix. This account is created by default during installation of the operating system. Most security consultants will recommend …
Read MoreTroubleshoot problem with yum update and rebuild the rpm database
I have created a step by step approach to troubleshoot a problem with performing yum update and how to rebuild the rpm database. I received and error while trying to …
Read MoreBooting Red Hat Linux into rescue mode.
Red Hat Linux can be booted into rescue mode from the installation CD, or any other boot method instead of the system’s hard drive. This also applies to other versions …
Read MoreIdentifying the kernel version and changing the default boot kernel in RedHat and Centos Linux.
Use the command uname to print system information in Linux. # uname -r 2.6.18-194.32.1.el5 The –r option will print the kernel release. # uname -s Linux -s prints the kernel …
Read MoreNslookup resolves address but ping is unable to resolve hostname on Unix server
I came across this issue on my newly built Solaris 10 server. I was able to ping a remote machine by Ip address, but not by its hostname. This indicated …
Read MoreHow to map to a remote NFS directory from a VMware ESX 4 server.
I ran into this error while trying to mount a NFS directory on a remote server from my Vmware ESX4 server. My Vmware esx server is called esx4-server and the …
Read MoreCreating RDM to LUN (SAN) mapping on VMware ESX 4, Vcenter.
In the past I have written articles about how to create a RDM to LUN disk mapping for VMware ESX 3. http://www.gamescheat.ca/2009/10/scripts-to-automate-the-process-of-identifying-and-compiling-an-rdm-to-lun-mapping-list-for-vmware-esx-30/ and http://www.gamescheat.ca/2009/10/how-to-identify-and-compile-an-rdm-to-lun-mapping-list-for-vmware-esx-30/ The procedure to identify the path …
Read MoreHow to list the status of swap in Solaris
List the status of all swap areas. # swap -l swapfile dev swaplo blocks free dev/dsk/c0t0d0s1 32,9 16 8425712 8425712 The output has five columns: path The path name for …
Read MoreUsing grep/egrep to find out which file contains a word or string in Unix or Linux
If you need to find out which file in a directory contains a specific word then the grep command is your friend. Here is an example, if you wanted to …
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