UNIX for Advanced & Expert Users

echo 'a,b,"cc,dd,ee",f,ii,"jj,kk",mmm' | \
  awk -v sep='"' '{
         for(i=1;i<=length($0); i++)
         {
            ch=substr($0,i,1)
            if(ch==sep) {inside=!inside}
            if (inside && ch==",") {continue}
            printf("%s",ch)
         }
         printf("\n")
       }'

 awk 'BEGIN{FS="\"";OFS=""}{gsub(",","",$2);gsub(",","",$4)}1' file

BEGIN{
        FS="\""
        OFS="\""
        }
        {for(i=1;i<=NF;i++)
                if(i%2 == 0)
                        gsub(/,/, "", $i)
        print
        }