Shell Programming and Scripting

chr1 100 200 "abc"
chr1 350 400 "abc"
chr2 450 600 "def"
chr2 612 780 "def"

chr1 100 400 "abc"
chr2 450 780 "def"

awk 'min[$4]=="" || $2<min[$4] {min[$4]=$2;lines[$4]=$1" "$2}END{for (j in lines) print j"\t"lines[j]}' inputfile
-------------------------------------
"abc"    chr1 100
"def"    chr2 450

awk 'max[$4]=="" || $3>max[$4] {max[$4]=$3;lines[$4]=$3" "$4}END{for (j in lines) print j"\t"lines[j]}' inputfile
-------------------------------------
"abc"    400 "abc"
"def"    780 "def"

awk ' { if(count[$4]++ == 0) {
                col1[$4] = $1
                min[$4] = $2
                max[$4] = $3
        } else {
                if(min[$4] > $2) min[$4] = $2
                if(max[$4] < $3) max[$4] = $3
        }
}
END {   for(i in count) print col1[i], min[i], max[i], i
}' input