Archive for the ‘Just Learnt Something New (JLSN)’ Category

brave browser – The following signatures were invalid: EXPKEYSIG 4FE13824E3FFC656 Brave Software

April 30, 2019 Leave a comment

Got the following error when trying to update. Mainly an issue with brave browser.

$ sudo apt-get update
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: bionic InRelease: The following signatures were invalid: EXPKEYSIG 4FE13824E3FFC656 Brave Software
W: Failed to fetch The following signatures were invalid: EXPKEYSIG 4FE13824E3FFC656 Brave Software
W: Some index files failed to download. They have been ignored, or old ones used instead

$ gpg --keyserver hkp:// --recv 4FE13824E3FFC656
$ gpg --export --armor 4FE13824E3FFC656 | sudo apt-key add -


Running on Ubuntu 18.0

Installing Graphite

April 19, 2016 Leave a comment

I needed to install graphite on a Ubuntu box on vagrant. The instructions on were not for the faint-hearted. But after 5mins on google I got the following guide from


Using Dnsmasq and nginx

March 11, 2016 Leave a comment

How to point a localhost to a different name. Eg localhost -> for use in local development?

One solution was dnsmasq. Simply updating /etc/hosts was not working for me. I think there was something else I was missing out on. Following the instructions on the website listed in the source section worked for me.


sudo: Unable to resolve host (none)

October 26, 2015 Leave a comment

I changed the host name of my machine from penguin to penguin_1 by editing both /etc/hosts and /etc/hostname.
After which I started getting the error “sudo: unable to resolve host (none)

Found it on askubuntu hidden among the many answers. You can not have an underscore as a name. When I changed penguin_1 to penguin-1 in both files my issue was resolved.


Interesting – Using Selenium

September 8, 2015 Leave a comment

Working with Redis

August 27, 2015 Leave a comment

What is Redis?

Redis is an open source, BSD licensed, advanced key-value cache and store. It is often referred to as a data structure server since keys can contain strings, hashes, lists, sets, sorted sets, bitmaps and hyperloglogs.

Download from and follow the installation instructions.

1. Start up the server

$ ./redis-server

           _.-``__ ''-._
      _.-``    `.  `_.  ''-._           Redis 3.0.3 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._
 (    '      ,       .-`  | `,    )     Running in standalone mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 6379
 |    `-._   `._    /     _.-'    |     PID: 17983
  `-._    `-._  `-./  _.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    | 
  `-._    `-._`-.__.-'_.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |
  `-._    `-._`-.__.-'_.-'    _.-'
      `-._    `-.__.-'    _.-'
          `-._        _.-'

17983:M 27 Aug 09:29:46.683 # Server started, Redis version 3.0.3
17983:M 27 Aug 09:29:46.683 * DB loaded from disk: 0.000 seconds
17983:M 27 Aug 09:29:46.683 * The server is now ready to accept connections on port 6379

2. Connect to the server using the commandline interface.

$ ./redis-cli> set "HLR:34" "{bar:'rab', foo:'oof'}"
OK> get "HLR:34"
"{bar:'rab', foo:'oof'}"

# To clear the database.> flushdb

# To quit.> quit


Restart fluxbox off the command line

May 7, 2015 1 comment

When switching between 1 and 2 screens, I kept on manually having to restart fluxbox.

fluxbox-remote command allows me to restart fluxbox using a script. As I already have a script that does the switching between 1 and 2 screens this was pretty neat.

To configure
1. Edit ~/.fluxbox/init change

session.screen0.allowRemoteActions: false
session.screen0.allowRemoteActions: true

2. Restart fluxbox using the menu.

3. Open a terminal and run the following command

$ fluxbox-remote restart