Linux

When installing Oracle 11g on Fedora 13 you may get the following error :               Error in invoking target ‘agent nmb nmo nmhs tclexec’ of makefile ‘/u01/app/oracle/product/11.1.0/db_1/sysman/lib/ins_emagent.mk Solution Within the file detailed in the error edit it and find the line that reads ‘$(MK_EMAGENT_NMECTL)’ change this to ‘$(MK_EMAGENT_NMECTL) -lnnz11’ Note : edit this file while … Read more

Below shows you the basic steps in order to configure your Linux Redhat / CentOS server as a Samba server. Install and Configure yum install samba -ychkconfig –level 123 smb on cd /etc/sambamv smb.conf smb.conf.backupvi smb.confcat > /etc/samba/smb.conf [paste the text below][global]workgroup = Workgroupnetbios name = SambaServerserver string = Samba Server %vlog file = /var/log/samba/log.%mencrypt … Read more

In this article we will show you how to set the time, date and timezone within CentOS. Though I’m sure this method will remain the same through the various Linux distributions. Steps Set the time zone Set the time and date Sync the hwclock with the current time and date Commands Below are the commands … Read more

In order to set the hostname on CentOS you will need to change the HOSTNAME section within /etc/sysconfig/network Your hostname will now be updated once you logout and then back in. Its also worth noting that this will survive reboots.

In order configure your Ubuntu/Debian box to access HTTP, HTTPS and FTP via a Proxy you will need to assign some environment variables. Assign Environmental Variables Below shows you the different variables you need to declare : export HTTP_PROXY=[PROXY IP]:[PORT]export HTTPS_PROXY=[PROXY IP]:[PORT]export FTP_PROXY=[PROXY IP]:[PORT] Survive reboot To survive a reboot you need to add these … Read more

Below is a basic template for setting up IPTables on a Linux box : Create LOGDROP CHAIN. Add LOG and DROP to chain. iptables -N LOGDROP iptables -A LOGDROP -j LOG –log-level 6 iptables -A LOGDROP -j DROP Create input and output policies iptables –policy INPUT DROP iptables –policy OUTPUT DROP Add inbound rules iptables … Read more

What is encoding / decoding ? Encoding refers to the process of translating a file into an ASCII based string. Decoding refers to the process of decoding the ASCII based string. In order to perform this decoding/encoding process Base64 is typically used. Base64 is a program that  converts each 6 bits and then converts this … Read more

Please note : This article is based on RHEL5 and grub. Below shows the 2 methods you can use to ensure serial connectivity when booting into single user mode. You may find without changing this setting your connection is lost just after Redhat starts booting.This configuration change can be via the grub.conf or via the … Read more

Issue When you try and run a yum update you receive the following error : root@localhost:/$ yum update Traceback (most recent call last): File “/usr/bin/yum”, line 4, in ? import yum File “/usr/lib/python2.4/site-packages/yum/__init__.py”, line 42, in ? import config File “/usr/lib/python2.4/site-packages/yum/config.py”, line 27, in ? from parser import ConfigPreProcessor File “/usr/lib/python2.4/site-packages/yum/parser.py”, line 3, in ? … Read more

In this article we will encrypt (using AES 256 cbc) and password protect (Salt the AES) a file using the openssl binary. The file we will encrypt will be the file secretfile.txt.As you can see it is just a plain text file. [root@linux tmp]# cat  secretfile.txt This is a secret file that we do not … Read more

When starting the httpd process you may receive the following error : Starting httpd: httpd: Could not reliably determine the server’s fully qualified domain name, using 127.0.0.1 for ServerName You might get this error when restarting Apache. To resolve the issue add the following to your httpd.conf file : ServerName 127.0.0.1

RRDtool is the OpenSource industry standard, high performance data logging and graphing system for time series data. The RRDtool homepage can be found here Below shows you how to install RRDtool 1.3.1 on Redhat Enterprise Linux. Update your system [root@localhost /]# yum install cairo-devel libxml2-devel pango-devel pango libpng-devel freetype freetype-devel libart_lgpl-devel make -y Download and … Read more

To install snmpwalk or snmpget on Redhat use the command yum install net-snmp-utilsThis will install the following binaries,  [root@localhost .ssh]# snmp snmpbulkget    snmpdelta      snmpinform     snmptable      snmptrapd snmpbulkwalk   snmpdf         snmpnetstat    snmptest       snmpusm snmpconf       snmpget        snmpset        snmptranslate  snmpvacm snmpd          snmpgetnext    snmpstatus     snmptrap       snmpwalk

Below shows you how to display line numbers within vi. Enable While in VI and not in `Insert Mode`type the following to display the line numbers : :set number Disable To disable line numbers enter the following : :set nonumber

Issue When trying to add a image to your CGI script you recieve the following error and the image isnt displayed. [root@localhost cgi-bin]# cat /var/log/httpd/error_log [Fri Jul 10 20:51:39 2009] [error] [client 10.2.2.5] Premature end of script headers: picture2.jpg, referer: [Fri Jul 10 20:57:57 2009] [error] [client 10.2.2.5] (8)Exec format error: exec of ‘/var/www/cgi-bin/picture2.jpg’ failed, … Read more

Issue You receive the following error when trying to run an application (such as rrdtool), No fonts found; this probably means that the fontconfiglibrary is not correctly configured. You may need toedit the fonts.conf configuration file. More informationabout fontconfig can be found in …. Solution Run yum install deja* If you receive the following,  –> … Read more

The alias command allows you to create command shortcuts within your shell. Below shows you how, move to your home directory, [root@localhost ~]# cd ~ add the alias of os which will show the output of ‘uname -a’ [root@localhost ~]# cat >> .bash_profile [root@localhost ~]# alias os=’uname -a’ Reload you environment variables for your new … Read more

The command below with present you with a random fact, lynx -dump  randomfunfacts.com | grep -A4 “\[3\]”| tail -n1 You can place it into your ~/.bash_profile file so that you receive a random fact everytime you log in.

The following command will retrieve your current IP city location, lynx -dump |sed -nr s/’^.*My IP address city: (.+)$/\1/p’

Issue After creating a new user account you may find that on login you recieve the following error, -bash: /dev/null: Permission denied -bash: /dev/null: Permission denied -bash: /dev/null: Permission denied  Solution /dev/null is a character special device which should have read+write permissions for everybody.Run the following to confirm the current permissions for /dev/null, ls -l … Read more