[Shell - HTTP] Useful http & web related commands

https.sh

# Download the SSL certificate from a website
echo | openssl s_client -servername NAME -connect HOST:443 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > FILENAME.cer

# copy ssh keys to remote server
ssh-copy-id remote_username@server_ip_address

# output recent server log
# https://explainshell.com/explain?cmd=tail+-f+%2Fpath%2Fto%2Flogs%2Ferror.log+%7C+grep+%27string%27
tail -f /path/to/logs/error.log | grep 'string'
cat /path/to/logs/error.log | grep 'string' 

# check HTTP header
curl -IL mysite.com