Example:

   wget -O- https://download.webmin.com/jcameron-key.asc | sudo gpg --dearmor | sudo tee /usr/share/keyrings/jcameron-key.gpg > /dev/null 2>&1 
   

Then need to edit the sources.list file to look something like:

   deb [signed-by=/usr/share/keyrings/jcameron-key.gpg] https://download.webmin.com/download/repository sarge contrib

For directories:

  find /desired_location -type d -print0 | xargs -0 chmod 0755
  

For files:

  find /desired_location -type f -print0 | xargs -0 chmod 0644

Adapt as required.

   find . -name '*altauserpoints*' -print0 | xargs -0 -P0 rm
   

Adapt as required.

   sed -i 's/foo/bar/g' *
   

To make the change through a whole directory tree:

   find ~/public_html/my_website/pages -type f -exec sed -i 's/2017/2018/g' {} \;
   

   grep -ir removed --include="*.txt" .
   

will search files with extension .txt ignoring case (-i)

Using this from the command line seems to do more than the GUI:

   bluetoothctl
   

Edit the file:

   /etc/systemd/journald.conf
   

and set SystemMaxUse, for example

   SystemMaxUse=250M

Then restart journal with:

   systemctl restart systemd-journald