The Network Information Service (NIS) facilitates the sharing of critical data stored in flat files among systems on a network. In managing a network consisting of many systems/hosts, it is often ideal to have a common repository (such as NIS) for storing user and group information traditionally stored in flat files such as /etc/passwd and /etc/group. Making such files available via NIS would allow any remote and properly configured NIS client machine to access or query the data contained in … [Read more...] about How to configure NIS services to use static port in CentOS/RHEL
How to Check if a Service Restart or Server Reboot is required After RPM Package Update (CentOS/RHEL/Fedora)
After reading this post you will know which services need to be restarted after updating one or more RPM packages. Also, you will know if a server reboot is needed after updating one or more RPM packages. needs-restarting utility of yum The command /sbin/needs-restarting out of the package yum-utils compares the mapped libraries of the running processes with their counterparts on disk and list processes with out of date copies in memory. The list allows identifying services and processes … [Read more...] about How to Check if a Service Restart or Server Reboot is required After RPM Package Update (CentOS/RHEL/Fedora)
11 Useful “ssh” and “scp” Commands in Linux
Introduction In this post, we are going to learn some useful ssh command and scp command with examples. SSH is a protocol that stands for Secure Shell which is a client-side command tool used to take remote session of Linux system securely. It uses Symmetrical and Asymmetrical encryption method to transfer data over the network. SSH is a highly recommended tool for taking a remote session of a server as it is the most secure way of connecting any server. SSH is the replacement of previously … [Read more...] about 11 Useful “ssh” and “scp” Commands in Linux
How to modify SNMP to run on custom port with tcp/udp and specific address in CentOS/RHEL
The Ask How to configure custom port (tcp OR udp) with particular interface ip address instead of binding all available interfaces (0.0.0.0)? The Answer SNMP by default runs and bind interfaces as follows (default port 161 and interface 0.0.0.0): # netstat -nlp | grep snmp tcp 0 0 127.0.0.1:199 0.0.0.0:* LISTEN 18824/snmpd udp 0 0 0.0.0.0:161 0.0.0.0:* 18824/snmpd ### bind default udp … [Read more...] about How to modify SNMP to run on custom port with tcp/udp and specific address in CentOS/RHEL
6 Bash Shell Command Line Chaining Operators in Linux
Introduction In this article, I will explain you 6 Bash shell command line Chaining Operators (Linux operator). Now let’s discuss what is chaining operator. Chaining operator is something which helps to run multiple commands at once like we execute a script and task completes automatically. Usually, people use Bash shell command line Chaining Operators (Linux operator) in shell scripting but also we can use these operators on shell prompt. Here we are going to discuss on below Bash shell … [Read more...] about 6 Bash Shell Command Line Chaining Operators in Linux
14 Useful “cat” Command Examples in Linux
Intoduction When learning Unix, it's common to first learn the cat command. An easy abbreviation to remember if you are pet-friendly, this command will concatenate the elements you specify into one package. The easiest way to look at files is to use cat, the concatenate command. In this article, we are going to learn how to use the Linux cat command. As discussed earlier, cat stands for Concatenate. cat command is a file management command in Linux used to display content of the file, create … [Read more...] about 14 Useful “cat” Command Examples in Linux
The System Activity Reporter (sar) Command in Linux
The System Activity Reporter, sar, can display a lot of information about your computer and save that information to files for later analysis. This program and its related tools are part of the sysstat package. When you install sysstat, a file named sysstat is added to the /etc/cron.d/ to call sar automatically. On Debian and most other distributions, the program is scheduled to run both at 10-minute intervals and once per day at 23:59. Depending on your distribution, sar is not called … [Read more...] about The System Activity Reporter (sar) Command in Linux
How to find which specific ethernet device corresponds to a specific port on a multi-interface network card in CentOS/RHEL
The Ask Can the Linux OS determine which physical port on a multi-interface network card an active ethernet device in the Linux OS corresponds to? The Answer There is no direct or guaranteed way to do this via the Linux OS, as it can depend on the server and network card hardware and firmware, however, there are multiple different ways to work out which ethernet device configured in the OS corresponds to which network adapter or port on a multi-interface network card. Method 1: if you … [Read more...] about How to find which specific ethernet device corresponds to a specific port on a multi-interface network card in CentOS/RHEL
Oracleasm Service Fails to Start After Upgrade to oracleasm-support-2.1.11-1 RPM Package
The Problem After upgrading oracleasm-support package, unable to start the oracleasm service which was working properly before the upgrade. Attempts to start the service result in: # service oracleasm start oracleasm is not enabled, use 'service oracleasm enable' or 'oracleasm init' The Solution This is caused by a regression in oracleasm-support-2.1.11-1 where the oracleasm configuration file /etc/sysconfig/oracleasm is not marked as a configuration file in the RPM spec file and is … [Read more...] about Oracleasm Service Fails to Start After Upgrade to oracleasm-support-2.1.11-1 RPM Package
Linux OS Service ‘kudzu’
Service Name kudzu Description This executes kudzu, the automatic hardware detection tool developed by Red Hat. "kudzu" detects and configures new and/or changed hardware on a system. It loads the required drivers and unloads redundant drivers. It is configured by default to run at system boot time to determine what hardware has been added or removed from the system. First, it compares hardware detected against information in /etc/sysconfig/hwconf (if it exists). Then it determines … [Read more...] about Linux OS Service ‘kudzu’