bash script help to parse out text
this is probably something very simple, but I can't seem to figure out how to do it..
I'm basically looking to parse out a section of text (four letters worth) from a text file and throw it into a variable for further processing in my script.. The text that I want to grab will always come from an exact location on the first line of the text file (20 characters in) and follows the text "s/n ****" in the string. **** is the text that I need to grab from the file.. It'll be a 4 digit string.
I was trying to figure out if I could use SED to do this but nothing seemed clear..
Thanks for the help in advance!