This is my solution to the Evernote bug https://discussion.evernote.com/forums/topic/120108-copy-paste-in-code-block-double-the-empty-lines/

evernote_code_block_without_double_empty_lines.sh

#!/bin/bash

convert_text(){
    python3 -c 'import html, sys; [print(html.escape(l), end="") for l in sys.stdin]' | \
    sed -E $'
        1i\\\n<span style="-en-clipboard:true;"><br/></span><div style="-en-codeblock:true;"><div>\n
        s, ,\&nbsp;,g
        s,$,<br/>,
        s,^<br/>$,<div><br/></div>,
        $a\\\n</div></div>\n
    '
}

convert_clipboard(){
    osascript -e "set the clipboard to «data HTML$(pbpaste | hexdump -ve '1/1 "%.2x"')»"
}   

main(){
    pbpaste | convert_text | pbcopy
    convert_clipboard
}

self_test(){
    convert_text <$BASH_SOURCE  
}

if [[ ${1:-} == "-t" ]]; then
    self_test
else
    main
fi