int StrFind(str s, str what)

Returns the position of the first occurence of what in s. If the string is not present, returns -1.

StrFind("abcdefabc", "def") -> 3
StrFind("abcdefabc", "abc") -> 0 // First occurence
StrFind("abcABCabc", "ABC") -> 3 // Case-insensitive
StrFind("abcdef", "xyz") -> -1   // Not found

int index = StrFind(s, "keyword");
if (index != -1)
    print(s:"Found the keyword at position ", d:index);
else:
    print(s:"Keyword not found");