Devops tutorials and examples

Command lscpu to find number of cpus on linux $ lscpu lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 32 On-line read more

To display keys added to ssh-agent using ssh-add, run the following commands. Lists fingerprints of all identities currently represented by the agent $ ssh-add -l read more

When using a bastion host (or Jumpbox) to connection to production server using ssh private keys, ssh agent forward can be used. The main advantage read more

Step to create swap partition on Ubuntu Linux. It should work on any other Linux also. Create storage file (say 4GB) using fallocate for swap read more

Sometimes we need a large file with any content on Linux. This may be needs for benchmarking and testing purpose. Here are some ways to read more

To find the inode number of a file on Linux/Unix the following approaches can be used. Find inode using ls $ ls -i file1.txt 412882 read more

Sometimes we need to truncate (make it size 0) a large opened file by a running process (e.h. php error log, apache error logs, custom read more

Swap space is the area on a hard disk which is part of the Virtual Memory. Swap space temporarily holds memory pages that are inactive. read more

You can use user and password based authentication to push git changes to GitHub. But it is cumbersome to type user and password with every read more

In case you have lost your ssh public key, you can re-generate it from the private key you have. Here is the command to generate read more

Curl is fairly handy command line utility to fetch a web page. It can also be used to automate various tasks in bash shell scripts. read more

Any user created on Linux may or may not have a password. Linux stores passwords in encrypted format in /etc/shadow. Here is quick command line read more

Giving sudo to a user is frequently occurring activity on Linux. Here are some scenarios and best practices for providing sudo to users on Linux. read more

Often we need to run a command as different users. Some of these users may not even have a login shell (e.g. www-data on Ubuntu read more

Adding a new user on Linux can be easily done on command line using useradd. These are some scenarios and handy commands to add a read more

Modifying a user on Linux can be easily done on command line using usermod. These are some scenarios and handy commands to modify a user read more

By default password based on login may be disabled on you Linux Server. Even though it is better to use private and public key for read more