Note book to help you and me remember some tricks

Month May 2022

Ansible inventory, best practices to manage ssh key with a bastion (jump host)

Ansible ssh key connection Refer to https://nicodevlog.com/2022/05/21/public-key-authentication-on-linux-best-practices-a-more-secure-way-to-connect-to-your-hosts-without-login-and-password/ The advantages of an ssh key over a basic authentication are: no raw password (but you can encrypt passwords using ansible vault) one unique private key to connect to several nodes (but of… Continue Reading →

Public key authentication on Linux – best practices: a more secure way to connect to your hosts without login and password

Note: for the whole article, I will work with a linux user called ansible on a host called also…ansible! 🙂 ssh-keygen When you use ssh-keygen you will generate a private and public key pair. And you’ll have to choose which… Continue Reading →

Install ansible 5 inside a python virtual environment with python 3.10.4

Note: The following commands are for RockyLinux, RedHat, CentOS, on other distros it will be almost the same. I’ve made the choice to connect to a user called ansible, and inside his home directory I’ve created a directory called ansible,… Continue Reading →

Python and virtual environments on Linux OS

Install python 3.10.4 from source on Rocky Linux or CentOS The following commands are executed as a root user. Virtual Python environment You can install several virtual python environments on your Linux OS. It will allow you to deploy a… Continue Reading →

How to empty a file with cmd or powershell? (equivalent of linux: cat /dev/null > pathtofile)

cmd version: The file is now 0 byte size, and occupies 0 byte on disk. powershell version: In this case, the properties of the file show us it’s now 2 bytes size then not completely empty. And the file uses… Continue Reading →

Why CRLF on Linux can sometimes be displayed as ^M with line feed?

Firstly, it’s good to remember these following points: CR is for Carriage Return LF is for Line Feed On windows line endings are represented by CRLF (CR+LF) On Linux line endings are represented by LF In a shell script you… Continue Reading →

Chrome Refused to display ‘https://othersite.mydomain.com/’ in a frame because it set ‘X-Frame-Options’ to ‘deny’.

In the DevTool of your web browser you have this kind of message because you’ve been to the url https://mydomain.com (or a completely different domain like https://anotherdomain.com) that contains an HTML page which includes an iframe of https://othersite.mydomain.com This message… Continue Reading →

Equivalent of Linux tail -f inside windows powershell

-Wait signifies wait for new logs and display it -Tail 10 signifies display the last 10 lines from <my_log_file>

Send an email on Linux with CLI or shell script without installing anything (no ssmtp required)

Prerequisites Basic example without encoding headers Case of an existing SMTP server without authentication (smtpserver.nicodevlog.com can be replaced by the domain name of your smtp server or its IP address): At the end you can see “\nSubject: TEST send mail… Continue Reading →

Shell script – Variables evaluation : display line endings \n and don’t cut your parameter function

How to pass string with several words and line endings \n as a parameter to a function Solution : Second test rst test : $myvar will be replaced by it’s value that contains a lot of words with spaces and… Continue Reading →

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