I want to split a 400k line long log file from a particular line number.
For this question, lets make this an arbitrary number 300k.
Is there a linux command that allows me to do this (within the script)?
line count (N):
wc -l file_name
top of file (first K lines):
head -n K file_name > top_file
bottom of file (L=N-K):
tail -n L file_name > bottom_file
Also, on second thought, split will work in your case, since the first split is larger than the second. Split puts the balance of the input into the last split, so
split -l 300000 file_name
xaa with 300k lines and
xab with 100k lines, for an input with 400k lines.