sudo certbot renew --dry-run
Category: Os
Empty File Using echo Command
# echo "" > access.log OR # echo > access.log
Note: You should keep in mind that an empty string is not the same as null. A string is already an object much as it may be empty while null simply means non-existence of an object.
For this reason, when you redirect the out of the echo command above into the file, and view the file contents using the cat command, is prints an empty line (empty string).
To send a null output to the file, use the flag -n which tells echo to not output the trailing newline that leads to the empty line produced in the previous command.
# echo -n "" > access.log
Another instance of Certbot is already running (Letsencrypt)
If it is not running, check whether there are .certbot.lock files in your system.
find / -type f -name ".certbot.lock"
If there are, you can remove them:
find / -type f -name ".certbot.lock" -exec rm {} \;
Add a command to list all certificates currently installed and their domains (Letsencrypt)
sudo certbot certificates
Letsencrypt
sudo certbot -i apache -a webroot -w /var/www/example.com/public_html -d example.com -d www.example.com
Setting permissions for wordpress
Everyone experiencing this issue should execute these commands:
sudo usermod -aG www-data $USER
Adds the currently logged in user to the www-data group.
sudo chown -R www-data:www-data /var/www
Changes the ownership of the /var/www directory to www-data group.
sudo chmod -R 755 /var/www
If this doesn’t fix the issue you’re having, you’ve got something else wrong and bashing DO is not going to help anyone. If you want a managed server, look for hosting elsewhere. If you need help, ask someone or hire an admin that knows how to not only ‘set things up’ but knows how to secure your server as well. You’ll be glad you did. DO is not for novices, even if they have a lot of tutorials.
How to display all user and groups by command
You can display with the help of compgen builtin command as follows:
To display all users run following command:
compgen -u
To display all groups run following command:
compgen -g
How to Edit the Hosts File in Mac OS X with Terminal
1. sudo nano /private/etc/hosts 1.1. put your changes 1.2. CTRL+O (press ENTER in order to save) 1.3. CTRL+X (to exit nano) 2. sudo killall -HUP mDNSResponder 3. dscacheutil -flushcache
Move all files to Parent directory
cd to/the/dir mv * ../
Merge multiple .csv files with the Mac OS X Terminal.app
cat *.csv >merged.csv