How to print variable value always as last column in CSV file - bash

Question

I have a list of CSV files, I have to print a variable name (dynamically; it will change), to last column in the CSV files.
Here is the code:
addProgramtypeID () {
for csv in $1
do
file_name="$csv"
echo $file_name
f=`echo $file_name | cut -d '_' -f3 | cut -d '.' -f1`
echo $f
k=`grep -i $f Program_type.csv | cut -d ',' -f3`
echo $k
awk '{ print $0 "," "'"$k"'" }' "$csv" > tempfile && mv tempfile "$csv"
done
}
addProgramtypeID "T_H_EDCGO.csv"
As of now the variable value K is being printed at the 1st column of the CSV file , also it is removing the first 2 characters of the first column in the file. My requirement is that the variable value should always come as the last column in the CSV file.
input :
TX_ID,SEQUENCE,PROGRAM_ID,CA_ID,C_ID
123,3,334,234,3
545,2,444,456,5
if suppose $k=2
output:
TX_ID,SEQUENCE,PROGRAM_ID,CA_ID,C_ID,2
123,3,334,234,3,2
545,2,444,456,5,2
Program_type.csv
type,desc,id
EDC,Alb,1
EDG,Gsc,2

Answer 1

Assuming there is is nothing nasty in your CSV file, you can use awk as follows:
for csv_file in $ALL_MY_FILES
do
cat csv_file | awk 'BEGIN{FS=","}; {print($(NF))}'
done
Or even just
cat $ALL_MY_FILES | awk 'BEGIN{FS=","}; {print($(NF))}'
Both of these will print the last line column of all the csv files. The results from each CSV are just appended together (is that really what you want?).
The difficulties are on the awk side. This completely unaware of things like quited strings
or extra whitespace. My recommendation is to try the line above, see what goes wrong (if anything) and then start tweaking.

Answer 2

It looks like what you want is just:
$ cat tst.sh
addProgramtypeID () {
csv="$1"
awk -v csv="$csv" '
BEGIN{ FS=OFS=","; split(csv,csvA,/[_.]/); f=csvA[3] }
NR==FNR { if ($0 ~ f) { k = $3 }; next }
{ print $0, k }
' Program_type.csv "$csv" > tempfile && mv tempfile "$csv"
}
addProgramtypeID "T_H_EDC.csv"
$ cat Program_type.csv
type,desc,id
EDC,Alb,1
EDG,Gsc,2
$ cat T_H_EDC.csv
TX_ID,SEQUENCE,PROGRAM_ID,CA_ID,C_ID
123,3,334,234,3
545,2,444,456,5
$ ./tst.sh
$ cat T_H_EDC.csv
TX_ID,SEQUENCE,PROGRAM_ID,CA_ID,C_ID,1
123,3,334,234,3,1
545,2,444,456,5,1
but it's hard to tell since your posted sample input could not produce your posted desired output so I had to make some up.
if ($0 ~ f) should probably just be if ($1 == f), I just copied what your original grep f <file> logic would do.