Suppose I have a list of URLs in a text file:

google.com/funny
unix.stackexchange.com/questions
isuckatunix.com/ireallydo

I want to delete everything that comes after '.com'.

Expected Results:

google.com
unix.stackexchange.com
isuckatunix.com

I tried **sed 's/.com*//' file.txt** but it deleted '.com' as well.