Shell Programming and Scripting

awk -F, -v P=10 -v R="DESCRIPTION" -v M="CURRENT_SALES" '
        NR == 1 {
                for ( i = 1; i <= NF; i++ )
                {
                        if ( $i == R )
                                d_pos = i
                        else if ( $i == M )
                                c_pos = i
                        else if ( i == P + 2 )
                                printf ( i == NF ? $c_pos OFS $i RS : $c_pos OFS $i OFS )
                        else
                                printf ( i == NF ? $i RS : $i OFS )
                }
        }
        NR > 1 {
                for ( i = 1; i <= NF; i++ )
                {
                        if ( i != d_pos && i != c_pos && i != P + 2 )
                                printf ( i == NF ? $i RS : $i OFS )
                        if ( i == P + 2 )
                                printf ( i == NF ? $c_pos OFS $i RS : $c_pos OFS $i OFS )
                }

        }
' OFS=, file

awk     'NR==1          {for (i=1; i<=NF; i++)  {if ($i == rem) RM=i
                                                 if ($i == rep) PL=i
                                                }
                         RCOL=10 + (RM<10) + (PL<10)
                        }
                        {for (i=1; i<=NF; i++)  {if (i == RCOL) printf ("%s%s", $PL, OFS)
                                                 if (i != RM && i != PL) printf ("%s%s", $i, OFS)
                                                }
                        print ""
                        }
        ' FS="," OFS="," rem="DESCRIPTION" rep="CURRENT_SALES" file
P_ID,P_NAME,COL5,COL6,COL7,COL8,COL9,COL10,COL11,CURRENT_SALES,COL12,
10,A,0,0,0,0,0,0,0,$100,0,
20,B,0,0,0,0,0,0,0,$400,0,
30,C,0,0,0,0,0,0,0,$800,0,