find a string in a file

i want to find a string in file then retrieve the rest,this is an
exemple of a line:
taske :say_hellow do
i want retrieve just "say_hellow"
so how can i do please.

Should be able to do something like to separate the tasks:

u = open( "myfile" )
      while line = u.gets
        if line.include?( "taske :" )
          anArray = line.split(' ')
          puts anArray[1] if anArray.length > 0

You could even combine the split function with the index function
line,split(' ')[1] if you are sure where the target info will be.

Note: Don't be afraid to try different things. This solution is only
one of many and others here could do a lot better. You could do better
with a little practice and research.