Viewing articles tagged 'linux'

How to Extend EXT2/3/4 and XFS root partition without LVM?

Steps to grow your KVM VM/Container’s partition after extending root OS size or extending...

How to Extend EXT2/3/4 and XFS root partition without LVM?

Steps to grow your KVM VM/Container’s partition after extending root OS size or extending...

5 Useful Examples of firewall-cmd command

The command-line tool firewall-cmd is part of the firewalld application, which is installed by...

6 Useful journalctl Command Examples in CentOS / RHEL 7 (Cheat Sheet)

Use the journalctl command to view the journal logs. By default, the listed entries include a...

About the ps and kill commands

Linux is a multitasking, multi-user system that allows all the processes to run simultaneously...

Apache HTTP server – most commonly used configuration directives

The main configuration file for Apache is /etc/httpd/conf/httpd.conf. Apache runs as installed,...

Apache HTTP server – most commonly used containers (special configuration directives)

Apache containers are special configuration directives that group other directives. The...

Beginners guide to Apache HTTP Server – Installation and Configuration

Apache HTTP server   The Apache HTTP Server, an open-source web server developed by the Apache...

Beginners Guide to DHCP – Install and configure DHCP server and client

Dynamic Host Configuration Protocol (DHCP) allows client machines to automatically obtain network...

Beginners guide to Kernel Module Configuration in Linux

The Linux kernel is loaded into memory by the boot loader. Kernel modules are dynamically loaded...

Beginners Guide to Linux Software Management with RPM

Maintaining Software Using RPM (Red Hat Package Manager)   RPM is a powerful software manager...

Beginners Guide to NFS in CentOS / RHEL

A Network File system (NFS) allows a server to share directory hierarchies (file systems) with...

Beginners Guide to Samba (Installation and Configuration)

Samba is an open-source implementation of the Server Message Block (SMB) protocol. It allows...

Beginners Guide to Swap Space Management in Linux

Swap space is used in Linux when there is insufficient physical memory (RAM) on your system to...

Beginners guide to vsftpd (installation and configuration) for CentOS / RHEL

File Transfer Protocol (FTP) is a commonly used method of downloading and uploading files between...

CentOS / RHEL 6,7 : How to increase system log message verbosity (rsyslogd)

The Linux system log daemon is responsible for logging system messages. Starting RHEL 6, The...

CentOS / RHEL 7 : GRUB2 configuration file /boot/grub2/grub.cfg explained

The GRUB2 configuration file /boot/grub2/grub.cfg – Starting RHEL 7 GRUB 2 is the bootloader....

CentOS / RHEL 7 : How to configure kdump using GUI

Kdump is the Linux kernel crash dumping mechanism. In the event of a system crash, Kdump provides...

CentOS / RHEL 7 : How to install and configure ftp server (vsftpd)

The FTP service/server is provided by the vsftpd daemon. Very Secure FTP Daemon (vsftpd) is the...

CentOS / RHEL 7 : sysctl kernel parameter doesn’t take effect after reboot

sysctl parameter didn’t take effect after a reboot on RHEL 7 server. Parameter...

CentOS / RHEL 7 : Unable To Start The Samba Service

The SMB service is unable to start, SAMBA shares can’t be accessed. Using systemctl fails to...

CentOS / RHEL 7 : unable to start vsftpd service

While starting or restarting the vsftpd service you might get below error on an RHEL 7 system. #...

CentOS / RHEL 7 : Understanding Kexec and Kdump

Kdump is the Linux kernel crash dumping mechanism. In the event of a system crash, Kdump provides...

CentOS / RHEL : How to add new swap partition

For the purpose of this post, let’s assume that you do not have any swap configured on your...

CentOS / RHEL : How to create and host yum repository over httpd

YUM (Yellowdog Updater, Modified) provide more services and functionality than is available with...

CentOS / RHEL : How to exclude kernel or other packages from getting updated using YUM Versionlock Plugin

Due to application certification and other restrictions in a production environment, it may be...

CentOS / RHEL : How to log all LVM commands

By default, the LVM configuration does not allow you to log the commands that are used in a shell...

DNS configuration file /etc/named.conf explained

The default configuration of the /etc/named.conf file provides a caching-only nameserver. The...

fdisk: Unable to write /dev/sdg: Bad file descriptor – error while formatting USB disk

While formatting a USB disk which was mounted in write-protected mode we are getting the below...

Fundamental Commands of Linux/Unix (with Examples & Syntax)

If you know the proper commands, File Management becomes easier. Following are the basic Linux...

How do I check if a port is in use on Linux?

Popular port numbers in Linux HTTP – TCP 80 HTTPS – TCP 443 POP3 – TCP 110 SMTP – TCP 25 SSH...

How to 'locate' files in the Linux Platform: 10 Helpful Commands

The failure in finding the easiest and yet more practical means of looking up files is one of the...

How to activate inode usage displaying in cPanel

  cPanel only   LVE Manager inodes Limits extension allows you to set inodes limits for your...

How to Add a File Based Swap for Linux?

We may want to add some swap space for a Linux box while only find that all disk space is...

How to add or delete a samba user under Linux?

To add a new user to access a samba share you need to first create a server user account using...

How to allow or deny Users to login to VSFTP Server on CentOS / RHEL?

After installation and start of the VSFTPD service, two files are created in the /etc/vsftpd/...

How To Auto Mount a FileSystem Using Systemd?

Below example shows how to create a systemd script to mount a disk under a specific path on...

How to Back Up and Restore XFS File Systems (xfsdump / xfsrestore)?

Use the xfsdump and xfsrestore utilities to back up and restore files in an XFS file system. You...

How to boot into rescue mode from installation DVD/ISO CentOS / RHEL 7 ?

When there is an issue with booting up RHEL / CentOS 7 system you can boot it into rescue mode...

How to calculate the size of hugepage used by a specific process/application on RHEL/CentOS 6,7?

You have a system configured with hugepages and you want to find per-process hugepages...

How to change the number of commands stored in Bash History?

The 2 environment variables which majorly affects the Bash History setting of saving the last run...

How to change the verbosity of debug logs during booting CentOS / RHEL 7?

Removing the rhgb and the quiet kernel command-line parameters, either by editing the...

How To Check a Disk for Bad Blocks or Disk Errors on CentOS / RHEL?

Hard disks can fail unexpectedly and it is always best to keep recent backups of all important...

How to check CPU temperature in Linux?

Device temperature control is, therefore, significant. Most of the time, your laptop computer...

How to check if a directory exists in Linux?

A directory is nothing but a location for storing files on the Linux system in a hierarchical...

How to check running process in Ubuntu Linux using command line

One can use the Ubuntu Linux command line or terminal app to display a running process, change...

How to check running process in Ubuntu using command line?

 To manage processes from the Ubuntu terminal The ps command is a traditional Ubuntu Linux...

How to check the status of a service using systemd on CentOS / RHEL 7 ?

Previous versions of CentOS/RedHat Linux use init scripts located in the /etc/rc.d/init directory...

How to clean YUM cache in CentOS / RHEL?

For some operations (for example, a yum install operation), Yum downloads the packages to install...

How to clear the buffer/pagecache (disk cache) under Linux

Are you facing a performance issue and you suspect it might be related to cache usage? High cache...

How to Configure ACL(Access Control Lists) in Linux FileSystem?

Traditional Linux access permissions for files and directories consist of setting a combination...

How to configure cache-only nameserver on CentOS / RHEL 7?

Caching-only nameservers, or recursive nameservers, offer resolution services but they are not...

How to configure DM-Multipath from an iSCSI initiator to an iSCSI target in CentOS / RHEL?

The procedure to configure DM-Multipath from an iSCSI initiator to an iSCSI target is presented,...

How to configure hugepages CentOS / RHEL 6,7?

HugePages is a feature integrated into the Linux kernel with release 2.6. This feature basically...

How to configure iSCSI Initiator (client) in CentOS / RHEL 7?

Internet Small Computer System Interface (iSCSI) is an IP-based standard for connecting storage...

How to configure iSCSI target using targetcli in CentOS / RHEL 7?

Internet Small Computer System Interface (iSCSI) is an IP-based standard for connecting storage...

How to configure multicast on an IP address (interface)?

Multicast can be used to send IP packets to a group of interested receivers. Compared with...

How to configure NTP server and client in CentOS / RHEL 7?

The Network Time Protocol (NTP) enables the accurate dissemination of time and date information...

How to configure VLAN Tagging using nmcli on CentOS / RHEL 7?

A VLAN is a type of local area network that does not have its own dedicated physical...

How to Convert Ext File Systems to Btrfs?

btrfs or Butter FS is a filesystem and has some interesting features:   One can have FS...

How to Create a New /boot Partition in CentOS / RHEL?

Here is a short howto on creating a new /boot partition in LVM and migrate the existing boot...

How to Create and Mount Btrfs Snapshots?

Btrfs is an open-source, general-purpose file system for Linux. The name derives from the use of...

How to create custom script to run automatically during boot CentOS / RHEL 7?

In RHEL 5 and 6, we were using automatic startup feature of RHEL through /etc/rc.d/init.d to run...

How to create partitions inside loopback device?

In most of the situations you would simply create a loopback device using “losetup” and mount it...

How to create virtual block device (loop device/filesystem) in Linux?

Linux supports a special block device called the loop device, which maps a normal file onto a...

How to delete a partition using fdisk?

The post list out the steps to delete a disk partition using fdisk command. Please note the...

How to delete an iSCSI Target on the initiator (iSCSI client)?

Internet Small Computer System Interface (iSCSI) is an IP-based standard for connecting storage...

How to determine number of CPUs on Linux using command line?

A CPU is an acronym for the central processing unit. It is an essential part of a computer. The...

How to disable all tty consoles and enable only 1 on CentOS / RHEL 7?

Upon system bootup there should be a single tty console running Xorg on it. New tty consoles are...

How to Disable and Blacklist Linux Kernel Module to prevent it from loading automatically on CentOS / RHEL?

To disallow the loading of malicious or unwanted modules, we can blacklist them. In order to...

How to disable cache on Linux Server?

You can disable the cache by adding the following to the .htaccess <Files...

How to disable firewalld and and switch to iptables in CentOS / RHEL 7?

By default, RHEL 7 uses the FirewallD service to provide network security. Firewalld may not be...

How to disable IPv6 on a specific interface only CentOS / RHEL 7?

We have already seen how to disable ipv6 globally on CentOS / RHEL 7. There could be an ask to...

How to Disable NUMA in CentOS / RHEL 6,7?

Non-Uniform Memory Access or Non-Uniform Memory Architecture (NUMA) is a physical memory design...

How to disable or delete virbr0 interface CentOS / RHEL 6,7 ?

If you check the ‘ifconfig -a’ after a fresh install of RHEL/CentOS 6,7 system, you would find...

How to disable Transparent Huge pages (THP) on CentOS / RHEL 7?

Explicit Huge Pages V/s Transparent Huge Pages   There can be two types of HugePages in the...

How to edit cronjobs for Linux OS?

A cron job is a Linux command used for scheduling tasks to be executed sometime in the future....

How to enable bind query logging to find out Who’s Querying a Name Server?

Bind query logging can be very handy if you are troubleshooting a problem. However, it generates...

How to Enable Disk Quotas on an XFS File System?

XFS supports disk quotas by user, by group, and by project. Project disk quotas allow you to...

How to enable IPv6 on CentOS / RHEL 7?

IPv6 is enabled by default on RHEL / CenOS 7 systems. So, if IPv6 was disabled on the system...

How to enable or disable XDMCP service (GDM) on CentOS / RHEL 6,7?

GDM can be configured to allow remote access via XDMCP (X Display Manager Control Protocol). We...

How to enable telnet for a group of users CentOS / RHEL 7?

In CentOS/RHEL 7, the /etc/pam.conf is depreciated and /etc/pam.d/remote will be used for...

How to Enable the Old ethX Style Network Interfaces Names on CentOS / RHEL 7?

At boot time (or whenever a network driver is loaded) interfaces are always assigned ethX style...

How to Enable Verbose Logging for VSFTPD?

The main configuration file for VSFTPD is ‘/etc/vsftpd/vsftpd.conf‘. When verbose logging is...

How to Enable X11 Forwarding on CentOS/RHEL 5,6,7?

To enable X11 Forwarding on a server client edit the file “/etc/ssh/ssh_config” and on ssh server...

How to Enable/Disable CPUs (Limiting CPU count) in CentOS / RHEL?

There are three ways to restrict number of CPU’s in CentOS/RHEL.   Using maxcpus parameter...

How to Extend allowed number of loopback devices?

A loopback device is used to access filesystems that are not associated with a block device (Hard...

How to Extend the Last Existing Filesystem Partition with Parted?

The post outlines the steps to extend the last partition of the disk and the filesystem residing...

How to find and replace ALL IP addresses with a new one?

In some situations, you need to change the VLAN IP address such as 172.0.0.2 with 172.0.0.1 for...

How to find CPU frequency in Linux?

The Central Processing Unit (CPU) is considered an essential component in any system. It is known...

How to find if NUMA configuration is enabled or disabled?

Non-Uniform Memory Access or Non-Uniform Memory Architecture (NUMA) is a physical memory design...

How to find Intel NUC BIOS version and model on Linux

Find out BIOS version, run: # dmidecode | less $ sudo dmidecode | less   How to check BIOS...

How to find the disk space allocated in Linux (CentOS /Red Hat .. . )

If the home directory, say /home, is a filesystem (mount point), then you could use df. If it's...

How to follow the mount order in /etc/fstab CentOS / RHEL 7 ?

With the introduction of systemd in RHEL 7 the boot process has become a lot faster because many...

How to Get a Specific String or Word in Files and Directories

This article will help you how to recursively dig into directories to find and list all files...

How to grow/extend XFS filesytem in CentOS / RHEL using “xfs_growfs” command?

Use the xfs_growfs command to increase the size of an XFS file system. The XFS file system must...

How to hide files and directories in Linux

I am a new Linux user. How do I hide files and directories in Linux operating systems using the...

How to install and configure Samba in CentOS / RHEL?

To provide printer and file sharing, Microsoft Windows uses a facility known as SMB (Server...

How to install and configure sosreport under CentOS / RHEL?

The sosreport tool collects information about a system, such as hardware configuration, installed...

How to install and configure telnet CentOS / RHEL 7?

It’s not recommended to use telnet as it is not secure. The passwords are transferred using a...

How to install and Configure VNC (TigerVNC) server in CentOS / RHEL 7

Virtual Network Computing (VNC) works by capturing the display’s frame buffer and making it...

How to install Ansible on Ubuntu 18.04 for IT automation

Ansible is an open source and free configuration management IT tool. It is similar to Chef or...

How to install FFmpeg on Fedora Linux 28/29 using dnf

FFmpeg is an open source and free software for managing video, audio, and other multimedia files...

How to install htop on Alpine Linux using apk?

Let us see all steps and command in details.   Alpine Linux install htop   Let us search for...

How to install kernel from rescue mode CentOS / RHEL 7?

A situation where the system has no kernel to boot from maybe because all the kernel are removed...

How to install networked HP printer and scanner on Fedora Linux?

You can download software by visiting this page . However, Fedora Linux includes software in its...

How to install Open Virtual Machine Tools for Virtual machines Hosted on VMWare in CentOS / RHEL?

Open VM Tools (OVT) consists of a suite of virtualization utilities that improves the...

How to install Scout_Realtime Monitoring Tool and Process Metrics in Linux?

Scout_Realtime is a simple, easy-to-use web-based tool for monitoring Linux server metrics in...

How to install VirtualBox 6 on Fedora Linux 29?

Introduction – Oracle VirtualBox is an open source and free hypervisor/virtual machine monitor...

How to Log all Bash History Commands to syslog (/var/log/messages) in CentOS/RHEL?

The user wants to see the list of commands used in the syslog messages. This way the user can...

How to make ethtool settings persistent across reboots in CentOS / RHEL 6,7?

Any change made with the ethtool program does not persist across reboots or network module...

How to map /dev/sdX and /dev/mapper/mpathY device from the /dev/dm-Z device?

Sometimes, to troubleshoot some multipath related issues, you would require to map the...

How to Modify GRUB2 Arguments with grubby CentOS / RHEL 7?

Starting RHEL 7, GRUB2 is the default boot loader. The configurations and settings of GRUB2 are...

How to modify the iSCSI initiator ID in Linux?

In our environment, we have duplicate initiator id in /etc/iscsi/initiatorname.iscsi due to...

How To Open A Port In CentOS / RHEL 7?

A TCP/IP network connection may be either blocked, dropped, open, or filtered. These actions are...

How to override content type with Nginx web server

Use the following curl command: curl -I url curl -I curl -I...

How to Prevent Users from Using the Last 10 Passwords CentOS / RHEL7?

The requirement here is that the user should not use the last 10 used passwords again when...

How to query and modify kernel parameters using sysctl (Immediately and persistently) in CentOS / RHEL?

The purpose of this post is to explain how to configure kernel parameters on Red Hat...

How to recover an interrupted yum package installation CentOS / RHEL 6,7?

For any reason, if the yum transaction was interrupted before it could complete, you would get an...

How to recover from a corrupt RPM database (rebuilding an RPM database)?

Why rpm database gets corrupted There can be multiple reasons which can lead to rpm database...

How to recover from deleted root entry in /etc/shadow and/or /etc/passwd files on CentOS / RHEL 7?

The ‘root’ entry was removed from /etc/shadow and /etc/passwd. How to recover the deleted root...

How to redirect HTTP to HTTPS automatically in Linux / cPanel?

If you have a secure certificate (SSL) on your website, you can automatically redirect visitors...

How to reinstall GRUB2 from rescue mode CentOS / RHEL 7?

CentOS / RHEL 7 now includes GRUB2 which uses a new way of installing to the MBR of your boot...

How to remove rescue image using grubby CentOS / RHEL 7?

To remove the default rescue image that gets installed when you install a CentOS/RHEL 7 system....

How to Remove virbr0 and lxcbr0 Interfaces on CentOS/RHEL 6,7?

There is only one Network card on machine but ifconfig shows 2 interface by name virbr0 and...

How to rename multiple folders in Linux using command line?

The mv command (mv source target) renames the file/folder named by the source operand to the...

How to Resize / Expand a Btrfs Volume / Filesystem?

It is a common task to resize/expand btrfs file system since btrfs is widely used in CentOS/RHEL...

How to restore/recover a deleted volume group in LVM CentOS / RHEL?

LVM takes a backup of the on-disk metadata before and after running any LVM operation on a...

How to run MariaDB as a custom user and group other than mysql on CentOS / RHEL 7?

So the requirement here is, we do not want to run MariaDB as the mysql user and group which is...

How to set date, time / NTP and timezone using timedatectl CentOS / RHEL 7?

RHEL 7 offers another utility to configure and display date and time information, timedatectl....

How to set nproc (Hard and Soft) Values in CentOS / RHEL 5,6,7?

This post outlines how a Linux System administrator can limit the allowed number of processes for...

How to set udev rules for ASM on multipath disks for CentOS / RHEL 7?

Udev is the mechanism used to create and name /dev device nodes corresponding to the devices that...

How to Set Up ModSecurity with Apache on Debian/Ubuntu?

The Apache web servers highly support customization and can be configured in multiple ways to...

How to Set “dev_loss_tmo” Value Persistently Using Udev Rule?

1. Check the attributes of the FC remote port(s) using the below command: # udevadm info...

How to specify command-line arguments and options when the dhcpd service is started CentOS / RHEL 7?

Dynamic Host Configuration Protocol (DHCP) allows client machines to automatically obtain network...

How to Throttle Bandwidth while applying yum package updates?

It is possible to limit bandwidth used by yum while downloading package updates using throttle...

How to troubleshoot iSCSI issues in CentOS / RHEL 6,7?

Internet Small Computer System Interface (iSCSI) is an IP-based standard for connecting storage...

How to troubleshoot NFS transfer latency issues using “nfsiostat” in CentOS / RHEL?

The nfsiostat command works like the iostat command except only for the NFS mount points. The...

How to Tune Btrfs Filesystem for Better Performance?

Btrfs is a filesystem which is very new and is still under development and benchmarking phase. As...

How to turn off Binary Logging in MySQL on Bitnami?

Did you want MySQL to turn off Binary logging in MySQL? The below article explains an easy way to...

How to upgrade Fedora 29 to Fedora 30?

Fedora Linux 30 released. This page shows how to use dnf system upgrade to upgrade your system to...

How to Use Iperf to Test Network Performance in Linux?

The iperf is a tool used for testing the network performance between two systems. The iperf...

How to use Magic SysRq tool in CentOS / RHEL?

SysRq utility In case your kernel freezes or/and hangs, you can use ‘magic’ SysRq tool. The...

How to use rndc command (command-line administration tool for named)?

The rndc utility is a command-line tool to administer the named service, both locally and from a...

How to Use “repoquery” Command to List Package Dependencies?

“repoquery” is a program for querying information from YUM repositories similarly to rpm queries....

How to use “xfs_admin” command to change parameters of an XFS filesystem?

Use the xfs_admin command to change the parameters of an XFS file system. You can also use the...

How to work with multiple java versions under Linux?

When i installed a new version of the Java Runtime Environment but the “java -version” command...

Install Chromium browser in Fedora 29 using dnf command

Chromium is a free and open source software created by Google. Chromium act as the upstream...

Install Google Chrome 73 on CentOS 7 using yum command

CentOS 7 install Google Chrome   Use wget command to grab Google Chrome 73 installer, run: $...

Installing Security Vulnerabilities with yum on CentOS/RHEL 5,6,7 (Cheat Sheet)

Here is a short note on List of Commands to Install Security Vulnerabilities with yum. To get...

Linux disable firewall command

Let us see how to stop and disable Firewalld on a CentOS or RHEL 7.x based system.   Is...

List of SELinux Utilities

This post lists some of the more commonly used command-line utilities for managing and operating...

Maintaining Linux filesystems using “fsck” and “tune2fs”

The best tool for maintaining file systems is fsck, which checks and repairs Linux file systems....

MySQL Fails to Start Using systemctl On systemd Linux Distributions

When trying to start MySQL using systemctl fails to start, for example: # systemctl status...

OpenLDAP Server and Client Utilities list

Lightweight Directory Access Protocol (LDAP) is used to access centrally stored information over...

pvcreate error : Can’t open /dev/sdx exclusively. Mounted filesystem?

So, here is the situation – pvcreate and vgcreate command throws errors shown below. # pvcreate...

pvcreate Fails With Error: “Device /dev/mapper/mpatha Not Found (or Ignored By Filtering).”

pvcreate command fails while using multipath device with below error even when the device is...

Running repairs on XFS Filesystems

The XFS File system is a high-performance journaling file system. XFS supports a maximum file...

Sample /etc/multipath.conf file

Below is a sample /etc/multipath.conf file taken from CentOS 7.4, from the directory...

TCP Wrapper (hosts.allow & hosts.deny) Command Options in Linux

TCP wrappers are capable of more than allowing and denying access to services. With the optional...

TCP Wrapper (hosts.allow & hosts.deny) Command Options in Linux

Internet Small Computer System Interface (iSCSI) is an IP-based standard for connecting storage...

The Linux “ps” Command Examples

The "ps" command in Linux is an abbreviation of "process status". It is used to get information...

The mtr command

The mtr(my traceroute) command, originally named Matt's traceroute, is a computer program that...

Understanding /etc/security/limits.conf file

UNIX/Linux operating systems have the ability to limit the number of various system resources...

Understanding /etc/xinetd.conf file in Linux

The xinetd daemon is a TCP wrapped super service which controls access to a subset of popular...

Understanding /etc/xinetd.d directory under Linux

xinetd daemon The xinetd daemon is a TCP wrapped super service which controls access to a subset...

Understanding chroot Jail

As the name implies, a chroot operation changes the apparent root directory for a running process...

Understanding DM-multipath deamon (multipathd)

The multipathd daemon checks for failed paths and reconfigures the multipath map. The daemon runs...

Understanding dm-Multipath Identifiers in Linux

By default, multipath devices are identified by a World Wide Identifier (WWID), which is globally...

Understanding DNS zone files

Information about domains in the DNS database is stored in zone files. A zone file consists of...

Understanding iscsiadm Utility in CentOS / RHEL

Internet Small Computer System Interface (iSCSI) is an IP-based standard for connecting storage...

Understanding kdump Configuration file /etc/kdump.conf

The configuration file for Kdump is /etc/kdump.conf. The default target location for the vmcore...

Understanding multipath Utility to Configure DM-Multipath

The multipath utility is the device mapper target auto-configurator, which is used to detect and...

Understanding RPM Versions and Naming Schemes

RPM is a powerful software manager which can be used to build, install, query, verify, update,...

Understanding Samba utilities – nmblookup, smbstatus, smbtar, testparm, wbinfo, smbget

The following list summarizes the command-line utilities included with the Samba packages. Use...

Understanding SELinux Booleans

A given SELinux policy can be customized by enabling or disabling a set of policy Booleans....

Understanding SELinux Policies in Linux

The SELinux policy describes the access permissions for all users, programs, processes, files,...

Understanding TCP Wrappers (/etc/hosts.allow & /etc/hosts.deny) in Linux

TCP wrappers provide basic traffic filtering of incoming network traffic. Access to “wrapped”...

Understanding the dm-multipath Configuration file /etc/multipath.conf

The main configuration file for DM-Multipath is /etc/multipath.conf. This file is not created by...

Understanding The sysfs File System (/sys) in Linux

In addition to /proc, the kernel also exports information to another virtual file system called...

What are different Samba Server Types?

Samba Server type is configured in the [global] section of the /etc/samba/smb.conf file. Below...

What are SELinux Modes and how to set them?

SELinux Modes SELinux runs in one of three modes (or states).   Enforcing This is the default...

What are SELinux Users and how to Map Linux Users to SELinux Users?

There are SELinux users in addition to the regular Linux users. SELinux users are part of an...

What are the Network Bonding Modes In CentOS / RHEL?

Network interface bonding is called by many names: Port Trunking, Channel Bonding, Link...

What Is GoAccess(A Real-Time Apache and Nginx) And How To Use It?

GoAccess is an interactive and real-time web server log analyzing programmer that instantly...

What is Rocky Linux And How to Download It?

Rocky Linux is one of the Linux distributions, and it is also based on Red Hat Enterprise Linux...

Where to find ASMLib / oracleasm RPMs for CentOS/RHEL, SUSE, OEL?

Here is a short note, if you are looking for packages (RPM) for Oracle ASMLib (oracleasm) for...

Why the files in /tmp directory gets deleted periodically on CentOS / RHEL 6,7?

In CentOS/RHEL 7, tmpfiles.d cleans up /tmp or /var/tmp by removing unused files. This function...

Yum Command Fails with “Another app is currently holding the yum lock” in CentOS/ RHEL 7

While issuing any yum command, you would get an error shown below: # yum list Loaded plugins:...

‘ip’ Command cheat sheet (Command Line Reference)

ip command provided by the iproute package is used to adjust addresses, link state, routing...

“btrfs” command examples to Create and Manage Btrfs File System

Btrfs is an open-source, general-purpose file system for Linux. The name derives from the use of...

“mount.nfs: access denied by server while mounting” – how to resolve

Mounting the nfs share from CentOS/RHEL NFS server on a NFS client gives error as shown below: #...