Identifying if a cell contains specific text

do you want to do it via code or would you prefer formulaes?? possible with both.

if you make the assumption that the word you want is split by '_' start and end you can try the below ...

=MID(A1,(FIND("_",A1,1)+1),(FIND("_",A1,(FIND("_",A1,1)+1))-(FIND("_",A1,1)+1)))

name of file in A1