Author: abhijit

change default sudo editor in visudo

March 15, 2018 / abhijit

For whatever reason, the default editor to change sudo permissions, which pops up when visudo is entered, is set to nano. I don’t have a clue why an option can’t be given on first use to change the editor.

The way to change it is to run the update-alternatives command

$> sudo update-alternatives --config editor

Which gives us these options.

Select 3 for vim.basic and we’re back to sanity.

ruby – ‘rvm not found’ when running cron or ssh command

February 14, 2018 / abhijit

rvm or the Ruby Version Manager, works perfectly fine when there is a single version of Ruby to be run on the system (among multiple versions installed, of course) around the entire system. In a production scenario, updating ruby itself is a task which is not taken lightly!

This worked perfectly until I encountered two quite different situations –

One scenario was where I wanted to execute a command via ssh into the server. So something like –

ssh user1@server1 'ruby ~/program.rb'

The other being when I wanted to run a ruby program via cron

In both these cases, I kept getting the error rvm not found. Initially, I couldn’t understand this at all, because every time I logged in and ran the program or the command it would run prefectly.

And then I learnt about the difference between a login and a non-login shell.

linux – user, group configuration

February 1, 2018 / abhijit

When I’m setting up a linux system, since it’s not very often, I have to keep looking up the basic commands for user setup.

I had started putting them in a text file and now it’s reached here!

set default cron editor

January 28, 2018 / abhijit

By default when crontab-e is run for the first time, we get the choice to set the editor.

The selected editor is stored in a file ~/.selected_editor

However, if the selected editor needs to be changed later, the command is –

select-editor

To reset or unset the selected-editor completely, we can remove the ~/.selected_editor file completely.

Ref: https://www.howtogeek.com/410995/how-to-change-the-default-crontab-editor/

Hello World!

January 24, 2018 / abhijit

This was the output of the first program that which I wrote in C. Before that, programs were about mathematical acrobatics.

It didn’t even strike me when I wrote the program. But then when I compiled it and ran it and I saw that ‘Hello, World!’ blinking on the screen I suddenly felt a vast expanse.

Suddenly, I was part of another world. A world out there, where people actually do useful things with computers. A world of learning.

And I’ve been programming ever since. And the first program I write whenever I learn a new language outputs this same line. Just so that I never forget that I’m just another programmer on a journey as so many others all over.