Backup files like so

Compress

tar -czvf name-of-archive.tar.gz /path/to/directory-or-file

Extract

tar -xzvf archive.tar.gz

Download with SCP

scp user@server:/path/to/remotefile.zip /Local/Target/Destination

example

scp sazerac@americanbourbonassociation.com:~/themes.tar.gz .

Export and import mysql

Change settings.php to reflect new mysql credentials

If you run into this error 
ERROR 1273 (HY000) at line 54: Unknown collation: 'utf8mb4_0900_ai_ci'

It's probably an issue with mysql 8 encoding not being available for 5.7 

Use this command in terminal as a workaround on the file

sed -i '' 's/utf8mb4_0900_ai_ci/utf8mb4_unicode_ci/g' <sql file here>

You could also just open the sql file in a text editor and

find and replace the string “utf8mb4_0900_ai_ci” with “utf8mb4_general_ci“.