System Administration Guides and Best Practices

Steps to extract, modify, update and rebuild initrd image in CentOS RHEL 7 and 8 ISO DVD with examples using XZ / LZMA format Update initrd with modules drivers

Configure secure logging to remote log server with rsyslog TLS certificates in CentOS/RHEL 7 Forward syslog to remote log server securely using TLS certificates

Step-by-Step Tutorial to transfer files over SSH using SSHFS between two Linux servers or Linux and WIndows server. Copy files between linux and windows using sshfs

Rsync and SCP recursive examples to copy directory and contents. scp from local to remote server and scp from remote to local. copy file from ssh to local or local to ssh server

Step by Step instructions to capture SSH and SSHD strace logs with DEBUG and VERBOSE. Add timestamps to SSH and SSHD debug and strace logs

Execute SSH and add timestamp to SSH verbose logs. Store the verbose logs into a log file and add timestamp prefix to each entry of log file with while loop

[Solved} Steps to debug and fix postponed publickey error leading to SSH connection failure. You may also get ROOT LOGIN REFUSED, Failed pubkey, permission issues with SSH

Step by step instructions to mount and unmount NFS share in Linux with examples. How to fix umount.nfs4:: device is busy

In this tutorial I will share the step by step instructions to run SSHD as non- root user in Linux platform. The same steps can be used for non privileged docker container pods and kubernetes

Configure thin provision lvm using kickstart and PXE server in CentOS/RHEL 7 and 8 Linux with examples. Define custom chunksize and metadata to create thinpool

Use chroot_local_user to restrict FTP user to a directory in vsftpd.conf in Linux. You can specify the directory name and path which acts as home directory for chroot

Linux NFS mount options example, Linux NFS exports options, root_squash vs no_root_squash, hard mount vs soft mount, Unix NFS performance. NFS mount options fstab

Grub files, also known as GRand Unified Bootloader, are essential components in the Linux operating system that facilitate the booting process. Grub files are

Configure postfix mail server and client using SMTP relay server. Check SMTP server configuration and connection with SWAKS. SMTP Mail Server CentOS/RHEL 7/8

To integrate Samba share with Active Directory we can use winbind to join Linux client with domain controller and use smbclient to access the windows share

Step by step tutorial to configure postfix using third party gmail smtp relay to send mails to external network. Use SASL with Google 2-Step Authentication

Step by Step guide tutorial on how to install and configure FreeIPA, ipa server LDAP, kerberos, DNS and IPA client on RHEL/CentOS 7 Linux with GUI and CLI

Step-by-Step Guide to create KVM Virtual Machine using Virtual Manager in RHEL and CentOS 8 Linux. Create VM, Take Snapshot, Assign Networks using Virtual manager GUI

How to grep multiple strings and patterns in single line from a file in Linux or Unix? Is it possible to grep multiple strings using single command from a file?

Step by step Guide to install Oracle Virtual Box on RHEL / CentOS 7 Linux. To install Oracle Virtual Box you need EPEL repo. Oracle Virtual 5.2 is out now

Steps to enable SSH access in linux rescue mode and configure network in rescue mode in RHEL/CentOS 7/8 with example transfer sosreport file inst.sshd=1

What is .swp file? Why this file is created? How to get rid of Found a swap file by the name warning? Another program may be editing the same file. An edit session for this file crashed

How to disconnect idle ssh session in Linux using ClientAliveInterval and ClientAliveCountMax. SSH close connection after sometime. How to close ssh connection

Steps to disconnect hung ssh session. Kill ssh session. Terminate stuck ssh session. Kill unresponsive ssh session. Disconnect pssh session in Linux

C++ provides several file I/O functions that enable programmers to write and read data from files. One of these functions is WriteFile, which is part of the

To find or get complete dependencies list of rpm you can use rpm, yum and repoquery command for both installed and non installed package

Tutorial guide to install systemtap (stap) to extract, filter and summarize data to enable diagnosis of complex performance. Systemtap Tutorial Linux

How to set default boot kernel in linux? Change the default boot entry for kernel ? Boot with old kernel version ? Revert to previous kernel version ?

How to delete iscsi target? Remove inactive iscsi target? Remove iscsi storage target from initiator? Remove iscsi virtual disk on CentOS / RHEL 7 Linux.

How to backup or copy and restore partition table in linux. linux clone partition table, linux repair partition table