Merging pre-sorted files without reading everything into memory

Question

I have a list of log files, where each line in each file has a timestamp and the lines are pre-sorted ascending within each file. The different files can have overlapping ti

Answer 1

You want to implement a file-based merge sort. Read a line from both files, output the older line, then read another line from that file. Once one of the files is exhausted, output all the remaining lines from the other file.