The test file I just split using this script on my i7 was about 1 GB in file size, had about 12 million lines of test and made 25 part files (each with about 500k lines each) – the processing took about 2 minutes and it didn’t go over 3 MB memory used at any point. The result is that it's exceptionally fast and it doesn't really need much memory to run. The benefit of this method is that it uses Text Streams, so the underlying data isn't loaded into memory (or, at least, not all at once). vbs script that can be run on any Windows computer (it gets automatically executed by the WScript.exe script host engine on Window).

So, I reverted back to my classic VBScript method and bashed together a small. And they're really big, so I need to split them into manageable parts (whilst preserving the header row). I often work with Comma Delimited and Tab Delimited ASCII files where a single line is a single record of data.

Will overwrite the early file numbers if llimit*100 is gearter than the number of lines in the file (cure by setting fcount to 1999 and use ~3 in place of ~2 in file-renaming line.) Note that I used llimit of 50000 for testing. MOVE /y '%sourcedir%ile$$.txt' '%sourcedir%ile%fcount:~-2%.txt' >NUL 2>nul I used a file named q25249516.txt containing 100Klines of data for my testing. Really depends on the characteristics of your target data. Now I'll not say that it'll be fast (less than 2 minutes for each 5Kline output file) or that it will be immune to batch character-sensitivites. Here's a native windows batch that should accomplish the task. SET 'dfile=%sourcedir%ile%fcount:~-2%.txt'

Text file splitter windows 10