[erlang-questions] Erlang version confusion

[lloyd@REDACTED]

Hello,

I have Erlang Version 19.0 installed long-ago on my dev system. While testing Nitrogen code my app crashed due to the pesky string library revision problem: string:lexemes/2 was not to be found.

OK, so time to update my working version of Erlang. I have kerl. Piece of cake. This was indeed successful:

$ erl
Erlang/OTP 22 [erts-10.4] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe]

However, when I try to rebuild my Nitrogen app, it still builds under Erlang Version 19.0. 

Here's kerl status:

$ kerl status
Available builds:
21.1,21.1
21.1,21.1-builtdocs
22.0,22.0
----------
Available installations:
21.1 /home/lloyd/Kerl/21.1
22.0 /home/lloyd/Kerl/22.0
----------
No Erlang/OTP installation is currently active

Looks like it might be useful to bring Version 19.0 under kerl. But, problem, I don't know how to decommission the old 19.0 installation.

Can anyone provide the magic incantation?

Many thanks,

LRP