Upgrade Debian 8 to Debian 9 through ssh

https://www.cyberciti.biz/faq/how-to-upgrade-debian-8-jessie-to-debian-9-stretch/

How to convert file encoding to/from UTF-8

Convert from UTF-8 to Windows cp 1252

$ iconv -f UTF-8 -t Windows-1252 file.csv > output.csv

Convert to UTF-8 from ISO-8859-15

$ iconv -f ISO-8859-15 -t UTF-8 file.csv > output.csv

How to check if a file is valid UTF-8

$ iconv -f UTF-8 your_file -o /dev/null

How to support full Unicode in MySQL databases

https://mathiasbynens.be/notes/mysql-utf8mb4