Split a file into two files at a given line
Solution 1:
A bit tighter solution:
(head -100 > f1.txt; cat > f2.txt) < input.txt
Solution 2:
Use awk, so that you need to make just one pass through the input file. The following
assumes you want the first 122 lines in the first file, and the remainder in the second.
awk 'NR < 123 { print >> "top_file"; next } {print >> "bottom_file" }' file_name