Helper (http://cht.sh/)

• curl cheat.sh/

Multiple screen on ssh/terminal

screen

// new screen
ctrl+a c

// next screen
ctrl+a n

// list screens
screen -ls

// close screen
exit

LS - https://www.tecmint.com/ls-command-in-linux/

• ls -la
  ls -lhF

delete

rm -r mydirectory

directory size

du -sh mydirectory
du -sh /path/to/directory
du -h mydirectory

How can I recursively delete all files of a specific extension in the current directory?

You don't even need to use rm in this case if you are afraid. Use find:

find . -name "*.bak" -type f -delete

But use it with precaution. Run first:

find . -name "*.bak" -type f

to see exactly which files you will remove.

CURL - test user agent block?

curl -IL -A "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; spider-feedback@bytedance.com)" https://www.mywebsite.com/