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Tuesday, January 28, 2014

You don't have permission to access /nagios/ on this server.

For this issue we have to just install php package and try to restart apache service and it should work with out any issu...

Friday, September 27, 2013

syntax error at abc.pl line 10, near "$h ("

Perl language have bit different mechanism when dealing with errors. Some points you should know before debugging errors. 1)Always use shebang statement with  -w option as shown below. #!/usr/bin/perl -w 2)Always use strict and warnings package to report all syntax errors. use strict; use warnings; When you get above error do not just check error on the given line try to check before and after the line of error report. This tip will resolve most of your errors like missing closing brace "}", sentence termination like ";", etc. ...

Can't find string terminator "EOF " anywhere before EOF at test.pl line 21.

This issue will come when you are using EOF or EOM string to send multiple line to a perl print statement or a command. Just have look at below code I have a file descriptor which will take input from a string as shown below. printf FD1 "this my first line"; This will work with out any issue, but when you want to send multiple lines as shown below we have to use PERL here-docs as shown below. printf FD1 << EOM; statement1 statement2 EOM other than this syntax, if you give any other thing it will fail. Observe that there is no double...

Tuesday, September 17, 2013

Can't open /dev/sdb1 exclusively. Mounted filesystem?

This is an issue we will get for many reasons, one reason we get this error is when we try to use the partition which is already mounted or used in your machine. This occurs some times due to LVM which is not properly implemented If you fee this is new partition and want to unlock the file from kernel follow below steps Step1: Check what are the partitions known to the kernel by using proc file system as shown bleow [root@gnani surendra]# cat /proc/partitions major minor  #blocks  name    8        0...

Wednesday, May 8, 2013

Perl Error: readdir() attempted on invalid dirhandle

Q. I am seeing "readdir() attempted on invalid dirhandle DIR at" error when attempting to open a directory using readdir function in Perl. How can I resolve this? The error "readdir() attempted on invalid dirhandle DIR at" clearly states that PERL was unable to open directory by using readdir function. There are number of situations which causes this error 1)Check if user who executed perl script have permissions on that directory or not. User should have read permissions to open a directory in Perl. Check permissions by using ls command. 2)Check...

Tuesday, May 7, 2013

Solution for: mv: cannot move `' to a subdirectory of itself,

Q. How can I move all my files in my working directory to a sub-directory with the working directory? I am getting error "mv: cannot move `' to a subdirectory of itself," Can I move all the files/folder to sub-directory with out this error? Yes, you can move all your files/folders present in your directory to a sub-directory with out getting that error. This error will occure when mv command try to move this sub-directory as well which it can not do and throws this error. All you have to do set shopt extglop...

Thursday, May 2, 2013

isohybrid: Warning: more than 1024 cylinders: isohybrid: Not all BIOSes will be able to boot this devic

Q. I am facing issue "isohybrid: Warning: more than 1024 cylinders:  isohybrid: Not all BIOSes will be able to boot this devic", How can I resolve this? First this is not an issue or error. This is just a warning not an error and it is just a warnning. This warning will be displayed when you are trying to convert a normal ISO file to hybrid ISO file by using isohybrid command isohybrid /path/to/normal/iso/file This error will come when your ISO file is more than 1GB siz...

Wednesday, February 27, 2013

error: Requested operation is not valid: Disk does not support snapshotting

error: Requested operation is not valid: Disk  does not support snapshot This error arises when you try to take a snapshot of a VM hard disk with virsh command as shown below virsh snapshot-create Clusterbase error: Requested operation is not valid: Disk '/path/to/kvm/clusterbase.img' does not support snapshot. If you see image of this VM is .img format, by default Virsh snapshot will work only for qcow2 format as of time of this post writing. So first convert that image to qcow2 format and then try to do a snapshot t...

Sunday, February 24, 2013

Loaded plugins:fastest mirror Loading mirror speed from cached hosfile Setting up install process Nothing to do

Q. I am seeing below error when installing some packages  Loaded plugins:fastest mirror   Loading mirror speed from cached hosfile   Setting up install process   Nothing to do This error will come when you execute below command yum install somepackage and the repo is set with "enable=0", try to change it or use --enablerepo= as shown below. yum --enablerepo=yourreponame install somepackage If you set enable=0 that indicates that dont include this repo when installing RPM packages. And enable=1 will include this...

Friday, February 22, 2013

error: command 'save' requires option

This error will come when you are trying to save VM using virsh command. When you try to save VM status using Virt-manager we no need to mention any file to save the status. Virt-manager will take care of saving it. But virsh have no mechanism like this. We have to provide a file to save the machine status. virsh save domaname filename Example virsh save linux1 /opt/linux1.sta...