5500 5700
5600 5800
5700 5800
5600 5900
5900 6100
5900 6100
5900 6100
5800 6000
5800 6100
5900 6100
5800 6200
5700 5800
I have a file with two columns as above. I need to find out min of every two rows in the first column and max of every two rows in the second column.How can it be achieved using awk? Desired output would be
Min Max
5500 5800
5600 5900
5900 6100
5800 6100
5800 6100
5700 6200
$ awk 'BEGIN { print "Min", "Max" } {a=$1; b=$2; getline; print ($1<a?$1:a), ($2>b?$2:b)}' data.in
Min Max
5500 5800
5600 5900
5900 6100
5800 6100
5800 6100
5700 6200
The awk code saves the current values in column one and two into the variables a and b respectively. It then reads the next line explicitly and prints the minimum of a and the new value in column one together with the maximum of b and the new value of column two.
($1 < a ? $1 : a) is using the ternary operator ?: to make a comparison and choose a value depending on the outcome of that comparison.
If you want tab-delimited output:
$ awk 'BEGIN {OFS="\t"; print "Min", "Max"} {a=$1; b=$2; getline; print ($1<a?$1:a), ($2>b?$2:b)}' data.in
Min Max
5500 5800
5600 5900
5900 6100
5800 6100
5800 6100
5700 6200
perl -pe '($_ .= <>) =~ s/(\d+) (\d+)\n(\d+) (\d+)/($3<$1 ? $3:$1).$".($4>$2 ? $4:$2)/e'
Append next line into the current record $_ and then compare field 3<->1 for min and 4<->2 for max and put the results within the record itself. -p will carry the result to stdout after that.