I have never seen one single GUI tool that did everything I needed or could do from the CLI. In Linux, there's always some setting or config you'll need to tweak to get your specific setup to work correctly.
If you start using a tool such as webmin (which is a great tool at that), you might run into a problem later down the road that webmin can't solve. Then you'll have to delve into the command line to fix it. Two problems with that:
- That's the worst time to learn command line, and you will probably mess things up worse.
- There is always more than one way to do any given task in Linux. So, if your GUI does things a certain way (usually a more advanced complicated way), then you try to do them yourself in CLI via another way (usually not the GUI way), you're asking for trouble.
Look at YaST for example. If you set a configuration in YaST and then go to edit the configuration file itself manually, you'll usually see a warning at the beginning of the file that warns not to mess with it, and that it's controlled by YaST.
Lots of people look for shortcuts and GUI's to admin linux boxes, but, in my opinion, those GUIs are really meant for people who already know what they're doing and know what's happening underneath and are just looking to save some time.
There's no two ways about it. Learning the command line is essential in Linux for administration and configuration. If you try to take shortcuts now, you will regret it later.