I use the tipical function:
....
Open file For Input As #1
...
ecc...

to reading txt file line by line.

But instead to init the redaing line by line...

1) I need to find, in position mid(line, 1,8), the string INIT0000 and strat the reading of lines from here
2) stop the reading of line from file wehen the code found in mid(line, 1,8), the string INIT0001

please a fast method to find the first line because have perphs 2.300.000 of lines in original txt file

note:
no possible duplicate string in position mid(line, 1,8)