You may have faced the issue when user root is not able to login in Red Hat and CentOS. Mostly the first thing which come into our mind is might be possible we forgot the password of root and we are not able to login. But apart of this there are other possibilities also which results the failure of root login.
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Keep logs of user after sudo su – : Secondary Logging
When we do sudo su – or su – and user become root we mostly found that in log it is not easy to track which command is used by which user. In this post, we will setup the secondary logging to Keep logs of root user after sudo access. You can also setup the […]
Non interactive ,without typing password do ssh to Server : By sshpass
Non interactive ,without typing password do ssh to Server : By sshpass Most of the time I found that there is always a question How to do ssh to Server without typing the passwd. I have one posted on bash scripting method with using expect command and there is one more method of passing RSA-DSA […]
How to Install awstat in Redhat and CentOS
Awstat is free log analizer tool which generates advanced web, streaming, ftp or mail server statistics, graphically. This post explains how to install awstat in Redhat and CentOS. Install and setup awstat Follow the steps to install and configure the awstat in your Red Hat based system. Step 1: Download the awstats. wget http://sourceforge.net/projects/awstats/files/AWStats/7.0/awstats-7.0-1.noarch.rpm Note: […]
How to delete password of user in Linux
This post will help you to delete password of user in linux. We should also know what is the exact reason we are deleting the password of user. User and group management in any operating system always play an important role. In Linux, sometimes we receive the request to disable the login of a user. […]
RSA key authentication in Linux : Passwordless login
In this post, we will learn how to configure the SSH RSA Key authentication in Linux servers. We will also setup the password less login between the servers.
GNU Screen
GNU Screen: It is a terminal multiplexer.By using GNU Screen, we can run many number of applications,interactive command shells, text editors, etc. within a single terminal. Inside the terminal user can open many windows terminal and sub-terminal. Installation: It can be installed in many flavours of Unix System.(I checked in all linux distro,AIX,Sun Solaris – […]
Saving every command and its output in log in Unix
In this post we will learn about saving every linux/unix command and its output in log file. The command called script will be use to save the command output in log. Run script command to save command output in file/log script filename.log Example: [root@server1 ~]# [root@server1 ~]# script my.log Script started, file is my.log Welcome […]
How to increase Password Expire date without resetting the password
How to increase Password Expire date without resetting the password It is commonly used that when we have to increase the password expire date of any user we simply reset the password of that user . But we can increase the Password Expire date of user without resetting the password. Here is the below scenario […]
Linux / Unix : 3 Commands to read file inside compressed .gz files without extracting
In this post we will learn about 3 simple commands by which we can read the files inside the compressed .gz file without extracting it.
In ESX , passwd: authentication information cannot be recovered
In ESX , passwd: authentication information cannot be recovered The ESX box has AD authentication. I was getting error when I am trying to reset user password by using command “passwd user_name” Whenever U get this error “passwd: authentication information cannot be recovered”,it means something is wrong in ur some /etc/pam.d files. In my case […]
df command not showing correct free space in linux
df not showing correct free space in linux In this post,I am sharing the troubleshooting. When we find the disk is full,we generally remove the files from that partition.Sometimes it is also observed that after removing files from the partiton. The df -h command,still shows partition is full. For this problem,follow the given below steps […]
script to change group from a file having list of users
In this post we are sharing the script to change group from a file having list of users. You can do the changes in script as per your requirement. The script is also using the /etc/group file to validate group names which could be existing in user supplied group file. Given below is the sample […]
Set and reset user password by bash script
In this post learn how to set and reset user password by bash script on Linux systems. It is quite good for Linux System Admin who wants to know how to set and reset user account password with bash script. We have used the standard input (stdin) with passwd command. Advantage: 1. Get the list […]
How to customize nologin shell message
In this post we will learn how to customize the nologin shell message for user on linux/unix system. This is very useful when you want to display your company strict legal security message to users who are trying to login into your servers. As we know that , nologin shell won’t allow user to login […]