Shell Programming and Scripting

#!/bin/sh

hdr=`cat inputfile.csv|grep 'Header'|awk -F"," '{ t += NF - 1 } END { print t }'`
hdr_str=`cat inputfile.csv|grep 'Header'`
hdr=`expr $hdr + 1`
while read line
do
  i=2;
  j=1;
  dte=`echo $line | awk -F"," '{ print $1 }'`
  k=2;
  str_tmp="";
  l=1;
  while [ $k -le ${hdr} ]
  do
    if [ $l -le 3 ]; then
      str_id_cur_iprv=`echo $hdr_str | awk -F"," '{ print $'$k' }'`
      if [ $l -eq 1 ]; then
        str_tmp=$str_id_cur_iprv
        l=`expr $l + 1`
        k=`expr $k + 1`
      else
        l=`expr $l + 1`
        k=`expr $k + 1`
        str_tmp=$str_tmp","$str_id_cur_iprv
      fi
    else
      break
    fi
  done
  str=${dte}","$str_tmp
  while [ $i -le ${hdr} ]
  do
    if [ $j -le 4 ]; then
      var=`echo $line | awk -F"," '{ print $'$i' }'`
      str=${str}","${var}
      i=`expr $i + 1`
      j=`expr $j + 1`
    else
      echo $str >> output_file.dat
      str=${dte}","$str_tmp
      j=1;
    fi
  done
  if [ $j -ne 1 ]; then
    echo $str >> output_file.dat
    str=${dte}","$str_tmp
  fi
done < inputfile.csv

awk 'BEGIN{FS=OFS=",";print "Date, index_id,currency,index_pro, level, net, total, mcap"}
NR==1{s1=$2 FS $3 FS $4; s2=$6 FS $7 FS $8; getline; next}
{printf("%s,%s,%s,%s,%s,\n", $1,s1,$2,$3,$4)}
{printf("%s,%s,%s,%s,%s,\n", $1,s2,$6,$7,$8)}
' inputfile.csv

awk '

BEGIN {
  OFS = FS = ",";
  Columns_by_set = 4;
  Infos_by_set   = 3; # Output columns count from header for each set
  print "Date","index_id","currency","index_pro",
               "level","net","total","mcap";
}

$1 == "Header" {
   Sets_by_line   = int((NF -1) / Columns_by_set);
   Fields_by_line = NF;

   for (set=1; set<=Sets_by_line; set++) {
      infos = "";
      field = 2 + (set-1)*Columns_by_set
      for (col=1; col<=Infos_by_set; col++) {
         infos = infos $(field+col-1) (col<Infos_by_set ? OFS : "");
      }
      Header_infos[set] = infos;
   }

   next;
}

$1 == "Date" {
   next;
}

Sets_by_line {
   if (NF != Fields_by_line) {
      printf("Invalid datas line %d: Fields count is %d, must be %d\n",
             NR, NF, Fields_by_line);
      next;
   }

   for (set=1; set<=Sets_by_line; set++) {
      datas = $1 OFS Header_infos[set];
      field = 2 + (set-1)*Columns_by_set
      for (col=1; col<=Infos_by_set; col++) {
         datas = datas OFS $(field+col-1);
      }
      print datas
   }
}
' inputfile

Header,4567,USD,BMI,,4568,USD,BMI,
Date,LEVEL,NET,TOTAL,MCAP,LEVEL,NET,TOTAL,MCAP
22-Dec-97,27.06492573,,20.9289574,,26.17032566,,20.60702136,
23-Dec-97,27.11627283,,20.96866346,,26.50090757,,20.86732796,
24-Dec-97,27.17448579,,21.01367878,,26.53347955,,20.89299111,
25-Dec-97,27.17854775,,21.02091981,,26.66484879,,20.99775394,
26-Dec-97,27.13228338,,20.98513719,,26.55463469,,20.91096371,
Header,9876,EUR,BMI,
Date,LEVEL,NET,TOTAL,MCAP
22-Dec-97,27.06492573,,20.9289574,
23-Dec-97,27.11627283,,20.96866346,
24-Dec-97,27.17448579,,21.01367878,
25-Dec-97,27.17854775,,21.02091981,
26-Dec-97,27.13228338,,20.98513719,

Date,index_id,currency,index_pro,level,net,total,mcap
22-Dec-97,4567,USD,BMI,27.06492573,,20.9289574
22-Dec-97,4568,USD,BMI,26.17032566,,20.60702136
23-Dec-97,4567,USD,BMI,27.11627283,,20.96866346
23-Dec-97,4568,USD,BMI,26.50090757,,20.86732796
24-Dec-97,4567,USD,BMI,27.17448579,,21.01367878
24-Dec-97,4568,USD,BMI,26.53347955,,20.89299111
25-Dec-97,4567,USD,BMI,27.17854775,,21.02091981
25-Dec-97,4568,USD,BMI,26.66484879,,20.99775394
26-Dec-97,4567,USD,BMI,27.13228338,,20.98513719
26-Dec-97,4568,USD,BMI,26.55463469,,20.91096371
22-Dec-97,9876,EUR,BMI,27.06492573,,20.9289574
23-Dec-97,9876,EUR,BMI,27.11627283,,20.96866346
24-Dec-97,9876,EUR,BMI,27.17448579,,21.01367878
25-Dec-97,9876,EUR,BMI,27.17854775,,21.02091981
26-Dec-97,9876,EUR,BMI,27.13228338,,20.98513719