how to find minimum and maximum of a data set
#minimum
cat your_data_file.dat | sort -nk3,3 | head -1
#this will find minumum of column 3
#maximun
cat your_data_file.dat | sort -nk3,3 | tail -1
#this will find maximum of column 3
#to find in column 2 , use -nk2,2
#assing to a variable and use
min_col=`cat your_data_file.dat | sort -nk3,3 | head -1 | awk '{print $3}'`