Split a file into several equal parts.

split-file-based-on-order.sh

#!/bin/bash

# File should have first column as numeric
FILE=$1

cat $FILE | sort -rn > $FILE.sort
cat $FILE.sort | awk 'NR%2==0' > $FILE.1
cat $FILE.sort | awk 'NR%2==1' > $FILE.2
rm -rf $FILE.sort

cat $FILE.1 | awk 'NR%2==0' > $FILE.a
cat $FILE.1 | awk 'NR%2==1' > $FILE.b
cat $FILE.2 | awk 'NR%2==0' > $FILE.c
cat $FILE.2 | awk 'NR%2==1' > $FILE.d

rm -rf $FILE.1
rm -rf $FILE.2

cat $FILE.a | awk 'NR%2==0' > $FILE.1
cat $FILE.a | awk 'NR%2==1' > $FILE.2
cat $FILE.b | awk 'NR%2==0' > $FILE.3
cat $FILE.b | awk 'NR%2==1' > $FILE.4
cat $FILE.c | awk 'NR%2==0' > $FILE.5
cat $FILE.c | awk 'NR%2==1' > $FILE.6
cat $FILE.d | awk 'NR%2==0' > $FILE.7
cat $FILE.d | awk 'NR%2==1' > $FILE.8

rm -rf $FILE.a $FILE.b $FILE.c $FILE.d