I am using and Raspberry Pi (running raspbian) and I have a shellscript continuously outputting values into textfile via this command:
wavemon -d |grep -i signal >> textfile.txt
The output is as shown below:
signal level: 20 dBm (100.00mW)
Question: How can I remove the other words (signal level: dBm (100.00mW)) and just input the number into the textfile so the textfile only shows the number (20)?