index - find a substring within a string
index
STR,SUBSTR,POSITION
index
STR,SUBSTR
Returns the position of the first occurrence of
SUBSTR in
STR at or after
POSITION. If
POSITION is omitted, starts searching from the beginning of the string. The return value is based at 0 (or whatever you've set the
$[
variable to--but don't do that). If the substring is not found, returns one
less than the base, ordinarily -1.