Shell Programming and Scripting

$ cat b.txt
script1,subject1,j@p.com,a@p.com,c@hi.com
script2,subject2,J@p.com,A@p.com,C@hi.com
script3,subject2,Jj@p.com,Aa@p.com,Cc@hi.com

awk '
BEGIN {
        FS=","
        pos=1
        email[1]=1
        sorted[2]=2
}
{
        delete email
        delete sorted
        script=$1
        subject=$2
        for(i=3;i<=NF;++i) {
                email[i-2]=$i
        }
        asort(email,sorted)

        printf("%s,%s",script,subject)
        for(i=1;i<=NF-2;++i) {
                printf(",%s",sorted[i])
        }
        printf("\n")
}' b.txt

$ ./b.sh
script1,subject1,a@p.com,c@hi.com,j@p.com
script2,subject2,A@p.com,C@hi.com,J@p.com
script3,subject2,Aa@p.com,Cc@hi.com,Jj@p.com

awk '
BEGIN {
        FS=","
}
{
        delete email
        delete sorted
        script=$1
        subject=$2
        for(i=3;i<=NF;++i) {
                email[i-2]=$i
        }
        asort(email,sorted)

        printf("%s,%s",script,subject)
        for(i=1;i<=NF-2;++i) {
                printf(",%s",sorted[i])
        }
        printf("\n")
}' b.txt

perl -F, -lape'
  $_ = join ",", @F[0,1], sort @F[2..$#F]
  ' infile