Question

I have a file, say all, with 2000 lines, and I hope it can be split into 4 small files with line number 1~500, 501~1000, 1001~1500, 1501~2000.

Perhaps, I can do this using:

cat all | head -500 >small1
cat all | tail -1500 | head -500 >small2
cat all | tail -1000 | head -500 >small3
cat all | tail -500 >small4

But this way involves the calculation of line number, which may cause error when the number of lines is not a good number, or when we want to split the file to too many small files (e.g.: file all with 3241 lines, and we want to split it into 7 files, each with 463 lines).

Is there a better way to do this?

Answer 1

When you want to split a file, use split:

split -l 500 all all

will split the file into several files that each have 500 lines. If you want to split the file into 4 files of roughly the same size, use something like:

split -l $(( $( wc -l < all ) / 4 + 1 )) all all