Remove amount of lines above and below a line containing a string

Question

I'm formatting GPS output logs and I need an efficient method to remove x number of lines above the line that contains a 0 and y number of lines below that line.

*--------------------------------------*
            UTC Time: 000000.00
           Latitude: 0000.0000
            N/S ind.: N
           Longitude: 0000.0000
         E/W ind: E
    Position fix ind: 0
     Satellites Used: 3
        MSL Altitude: 00.0
*--------------------------------------*

If the line contains "Position fix ind: 0", remove 6 lines above it and remove 3 lines below in and remove the line it is in

EDIT:

The input file is a .log file

EDIT 2:

input file

1
2
3
*--------------------------------------*
            UTC Time: 000000.00
           Latitude: 0000.0000
            N/S ind.: N
           Longitude: 0000.0000
         E/W ind: E
    Position fix ind: 0
     Satellites Used: 3
        MSL Altitude: 00.0
 *--------------------------------------*
3
2
1
1
2
3
*--------------------------------------*
            UTC Time: 000000.00
           Latitude: 0000.0000
            N/S ind.: N
           Longitude: 0000.0000
         E/W ind: E
    Position fix ind: 5
     Satellites Used: 3
        MSL Altitude: 00.0
*--------------------------------------*
3
2
1

Answer 1

def remLines(infilepath, outfilepath, delim, above, below):
    infile = open(infilepath)
    outfile = open(outfilepath, 'w')
    buff = []
    line = infile.readline()
    while line:
        if line.strip() == delim:
             buff = []
             for _ in range(below): # need to error check here, if you're not certain that your input file is correctly formatted
                 infile.readline()
        else:
            if len(buff) == above:
                outfile.write(buff[0])
                buff = buff[1:]
            buff.append(line)
        line = infile.readline()
    outfile.write(''.join(buff))

if __name__ == "__main__":
    remLines('path/to/input', 'path/to/output', "Position fix ind: 0", 6,3)

Testing:

Input:

1
2
3
*--------------------------------------*
            UTC Time: 000000.00
           Latitude: 0000.0000
            N/S ind.: N
           Longitude: 0000.0000
         E/W ind: E
    Position fix ind: 0
     Satellites Used: 3
        MSL Altitude: 00.0
 *--------------------------------------*
3
2
1
1
2
3
*--------------------------------------*
            UTC Time: 000000.00
           Latitude: 0000.0000
            N/S ind.: N
           Longitude: 0000.0000
         E/W ind: E
    Position fix ind: 5
     Satellites Used: 3
        MSL Altitude: 00.0
*--------------------------------------*
3
2
1

Output:

1
2
3
3
2
1
1
2
3
*--------------------------------------*
            UTC Time: 000000.00
           Latitude: 0000.0000
            N/S ind.: N
           Longitude: 0000.0000
         E/W ind: E
    Position fix ind: 5
     Satellites Used: 3
        MSL Altitude: 00.0
*--------------------------------------*
3
2
1