method driver /usr/lib/apt/methods/https// could not be found


Every time I would run apt-get update, I would get the error below:

implementer@whiscardz ~ $ sudo apt-get update

Reading package lists... Done
E: The method driver /usr/lib/apt/methods/https// could not be found.
E: Failed to fetch https//://
E: Some index files failed to download. They have been ignored, or old ones used instead.


And this was affecting the opera developer source list.

If you look closely at the url you’ll notice there is a typo the : should come before //

E: Failed to fetch https//://

Solution was to therefore edit the file:

implementer@whiscardz ~ $ sudo vim /etc/apt/sources.list.d/opera
opera-developer.list opera.list
implementer@whiscardz ~ $ sudo vim /etc/apt/sources.list.d/opera-developer.list

deb stable non-free #Opera Browser (final releases)
implementer@whiscardz ~ $ sudo apt-get update

This time cache update runs fine without errors.


How do I fix a “E: The method driver /usr/lib/apt/methods/http could not be found.” error?

gpg: 3310B567: There is no assurance this key belongs to the named user


I was getting the above error when trying to encrypt a file using a public key that I just imported.


Sign the public key. Before you sign it you must ensure that you also have a public private key of your own so that you can sign someone else’s public key.

  • Edit the key and get the finger print and confirm with the owner of the key whether the key is correct. You can do this by phone or text or whichever method:

implementer@whiscardz ~ $ gpg --edit-key whiscard [68/600]
gpg (GnuPG) 1.4.20; Copyright (C) 2015 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

pub XXXX/XXXXXXX created: 2017-XX-XX expires: never usage: SC 
 trust: unknown validity: unknown
sub XXXX/XXXXXXX created:2017-XX-XX expires: never usage: E 
[ unknown] (1). Imela (whiscard) <>

gpg> fpr
pub XXXX/XXXXXXX  2017-XX-XX Imela (whiscard) <>
 Primary key fingerprint: FFFF 40CD 8888 DA4E 96CB UUUU 3C4B YT89 6AF0 PPPP

  • Sign, check and then quit to exit

gpg> sign

gpg> check

gpg> quit


Exchanging keys

gnupg: There is no assurance this key belongs to the named user

Why is gpg getting upset and how do I stop it?

gpg encrypt file without keyboard interaction

Importing gpg public key


Needed to import a binary .gpg public key into my keyring for use in encrypting documents


Used the following command to import the key:

implementer@whiscardz ~ $ gpg --list-keys 
implementer@whiscardz ~ $ gpg --import imela.gpg 
gpg: key XXXXXX: public key "Imela (whiscard) <> imported
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
implementer@whiscardz ~ $ gpg --list-keys 
uid Imela (whiscard)<>



Importing a public key

Generate gpg key pair


Needed to generate a gpg key pair for encryption and decryption of documents.


Since gpg is mostly always installed on a linux system by default, I just ran the following command and used the default options except for the key size:

imela@curtsey ~ $ gpg --list-keys
imela@curtsey ~ $ gpg --gen-key
gpg (GnuPG) 1.4.20; Copyright (C) 2015 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Please select what kind of key you want:
(1) RSA and RSA (default)
(2) DSA and Elgamal
(3) DSA (sign only)
(4) RSA (sign only)
Your selection?
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 4096
Requested keysize is 4096 bits
Please specify how long the key should be valid.
0 = key does not expire
<n> = key expires in n days
<n>w = key expires in n weeks

<n>m = key expires in n months [136/410]
<n>y = key expires in n years
Key is valid for? (0)
Key does not expire at all
Is this correct? (y/N) y

You need a user ID to identify your key; the software constructs the user ID
from the Real Name, Comment and Email Address in this form:
"Heinrich Heine (Der Dichter) <>"

Real name: Imela
Email address:
Comment: whiscard
You selected this USER-ID:
"Imela (whiscard) <>"

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O
You need a Passphrase to protect your secret key.

We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
[0] 0:[tmux]* 1:bash 2:bash 3:[tmux]-

  • Now when you list you will see the following gpg key that was generated:

mela@curtsey ~ $ gpg --list-keys
uid imela (whiscard) <>


Generating a new GPG key


Add youtube-dl ppa install latest youtube


Needed to update the latest version of youtube-dl on Linux Mint.


  • use wget or curl to download the youtube-dl latest binary:

# curl -o /usr/local/bin/youtube-dl
# wget -O /usr/local/bin/youtube-dl
  • Then make it executable:
# chmod a+rx /usr/local/bin/youtube-dl
  • Alternatively you can add a third party PPA and then install youtube-dl:
$ sudo add-apt-repository ppa:nilarimogard/webupd8
$ sudo apt-get update
$ sudo apt-get install youtube-dl

To update:

# youtube-dl -U


Install YouTube-DL in RHEL/CentOS and Fedora

Installing Microsoft True Type Core Fonts on Debian based Docker Image


I had a problem where one of the jasper reports loaded onto a docker image based on Debian Jessie was not running.

It was throwing this error, “font arial not available to jvm”


Add the following mirror to the sources.list file:

root@host:/usr/local/# cat /etc/apt/sources.list
deb jessie main contrib

Then do apt-get update and then install the ttf-mscorefonts-installer package:

root@host:/usr/local/# apt-get update

root@host:/usr/local/# apt-get install ttf-mscorefonts-installer

Then restart the docker image.


Download Page for ttf-mscorefonts-installer_3.6_all.deb

Font ‘Arial’ is not available to the JVM. See the

Font ‘Arial’ is not available to the JVM