Splitting file needs speedup

Shell Programming and Scripting
1

I've got a large file (2-4 gigs), made up of 4 columns. I'd like to split the file into two, based on the 2nd column value being even or odd. The following script does the job, but runs incredibly slow--I'm not sure it will complete this week.

There must be a clever way to do this with just awk.

#!/bin/bash
while read line
do
    tmp=`echo $line| awk '{print $2}'`
    tmp=$(( $tmp % 2))
    if [ $tmp -eq 0 ]
    then
        echo $line >> even.dat
    else
        echo $line >> odd.dat
    fi
done < input.dat
2 
awk '{print >$2%2".dat"}' infile

you will get 2 files: 0.dat (even number) and 1.dat (odd number)

1 Like
3

That's what I needed.