nixCraft Linux / UNIX Newsletter

A haiku about DNS

Posted: 18 Apr 2017 02:28 PM PDT

Here is a haiku (a Japanese poem) about DNS (“domain name system”):

It’s not DNS
There is a no way it’s DNS
It was DNS

Here is a postcard for your sysadmin friend whenever there is a DNS issue:

dns haiku

Humor: Binary Search Trees

Posted: 18 Apr 2017 02:19 PM PDT

Daughter: Dad, you know Binary Search Trees?

Dad: Say no more.

Binary Search Trees (Pic credit)

Dad: *later* Now watch as I delete and re-balance!

Daughter: DAD, NOOOOO!

There is always xkcd for everything, so here is the one:

Xkcd – Binary trees

How to execute sudo without password?

Posted: 18 Apr 2017 01:59 PM PDT

If you are the only sysadmin or developer, you can skip password when you run sudo command. By default, sudo asks for the password. Here is how you can run sudo without having to enter your password.

I’m a new Unix system user. How do I use sudo command without a password on a Linux or Unix-like systems? I log in as tom@my-cloud-server-ip and disabled root login for ssh. After login, I need to run some commands as root user. I am the only sysadmin using my server. How do I run or execute sudo command without a password for a user named Tom under Debian/Ubuntu/CentOS Linux cloud server?

How to run sudo command without a password on a Linux or Unix

How to flush/clear the pfsense DNS forwarder cache

Posted: 18 Apr 2017 01:47 AM PDT