I am looking in a `/etc/hosts` file for hosts that should contain servers that look at least like this:

```
mobile.example.com
more.mobile.example.com

```

and NOT example.com

I want to search with a wildcard like this:

`sed`/`awk`/`find`/`grep`/ `word.word.word < path/to/inputfile > path/to/outputfile` where word consists of `[A-Z, a-z, 0-9]` 

Please write 'sed','awk','find' or 'grep' code for this.