Converting CSV file to multiline text file - bash

Question

I have file which looks like following:
C_DocType_ID,SOReference,DocumentNo,ProductValue,Quantity,LineDescription,C_Tax_ID,TaxAmt
1000000,1904093563U,1904093563U,5210-1,1,0,1000000,0
1000000,1904093563U,1904093563U,6511,2,0,1000000,0
1000000,1904093563U,1904093563U,5001,1,0,1000000,0
1000000,1904083291U,1904083291U,5310,4,0,1000000,0
1000000,1904083291U,1904083291U,5311,3,0,1000000,0
1000000,1904083291U,1904083291U,6101,6,0,1000000,0
1000000,1904083291U,1904083291U,6102,1,0,1000000,0
1000000,1904083291U,1904083291U,6106,6,0,1000000,0
I need to convert it to text file which looks like this:
WOH~1.0~~1904093563Utest~~~ORD~~~~
WOL~~~5210-1~~~~~~~~1~~~~~~~~~~~~~~~~~~~~~
WOL~~~6511~~~~~~~~2~~~~~~~~~~~~~~~~~~~~~
WOL~~~5001~~~~~~~~1~~~~~~~~~~~~~~~~~~~~~
WOH~1.0~~1904083291Utest~~~ORD~~~~~~
WOL~~~5310~~~~~~~~4~~~~~~~~~~~~~~~~~~~~~
WOL~~~5311~~~~~~~~3~~~~~~~~~~~~~~~~~~~~~
WOL~~~6101~~~~~~~~6~~~~~~~~~~~~~~~~~~~~~
WOL~~~6102~~~~~~~~1~~~~~~~~~~~~~~~~~~~~~
WOL~~~6106~~~~~~~~6~~~~~~~~~~~~~~~~~~~~~
The output file has header record and line item record. Header Record contains the SOReference and some hardcoded fields and the Line Item record contains the Product Value and Quantity associated to that SOReference . In the input file we have 2 unique SOReferences thats why the the output file contains 2 header record and their associated line items record.
Need something being done as a command line (awk/sed)? since I have a series of files like this one which need to be converted to text.

Answer 1

With AWK, please try the following:
awk -F, '
FNR==1 {next} # skip the header line
{
if ($2 != prevcol2) { # insert newline when SOReference changes
nl = FNR<=2 ? "" : "\n" # suppress the newline in the 1st line
printf("%sWOH~1.0~~%stest~~~ORD~~~~\n", nl, $2)
}
printf("WOL~~~%s~~~~~~~~%s~~~~~~~~~~~~~~~~~~~~~\n", $4, $5)
prevcol2 = $2
}' file.csv