asdf install erlang for ubuntu

asdf install erlang.md

1. according the asdf document to install lib before run

asdf install erlang 21.3.4

2. if you meet warning,

documentation : 
                xmllint is missing.
                Using fakefop to generate placeholder PDF files.

then you need to run,

sudo apt-get install libxml2-utils

if the warning is

jinterface     : No Java compiler found

then you should run,

sudo apt-get install default-jdk

to install jdk

For macOS:

After Install asdf, need to set the env:

echo 'source /usr/local/opt/asdf/asdf.sh' >> .zshrc