[Solved] How to find the n’th byte in a file [closed]

Question

One solution in your case (unless you have strict restriction on space usage) would be to copy your file into another skipping bytes that you do not need. Depends on how you count nth byte you may need to open files in binary mode. You may rename source file to temp open new file with original name, do actual copy and delete source. Or you can copy content to temp file, then delete original and rename temp into original name.
If you have restriction on disk space you can store file remaining (from 150,000th to the end in your example) truncate original file to 100,000th and then copy that remaining back.

Accepted Answer

One solution in your case (unless you have strict restriction on space usage) would be to copy your file into another skipping bytes that you do not need. Depends on how you count nth byte you may need to open files in binary mode. You may rename source file to temp open new file with original name, do actual copy and delete source. Or you can copy content to temp file, then delete original and rename temp into original name.
If you have restriction on disk space you can store file remaining (from 150,000th to the end in your example) truncate original file to 100,000th and then copy that remaining back.