I have a CSV file. For example columns:
col1, col2, col3, col4, col5 I need to restructure it as
col1, col2, new_col1, col3, new_col2, col4, new_col3, col5. The values in the rows will be null. I am assuming this has to be done with awk.
I tried the questions already in StackOverflow, but all I am getting is to add at the end or beginning. I need to be able to specify column number/position where the column name needs to be added.
remark: This answer assumes that no CSV field entry has <double-quoted> strings ("string") with embedded <comma>- or <newline>-characters.
If the above is not applicable to you problem, other approaches are needed. Useful links:
If you want to add a column to a CSV file, you can do the following:
add a column at the beginning:
awk 'BEGIN{FS=OFS=","}{print new_value OFS $0}' file add a column at the end:
awk 'BEGIN{FS=OFS=","}{print $0 OFS new_value}' file add a column before column n:
awk 'BEGIN{FS=OFS=","}{$n=new_value OFS $n}1' file add column after column n:
awk 'BEGIN{FS=OFS=","}{$n=$n OFS new_value}1' file add a column before each of column n1 < n2 < ... < nm: (start at the back)
awk 'BEGIN{FS=OFS=","; split("n1,n2,n3,...,nm",a)} {for(i=m;i>0;--i) $(a[i])=new_value OFS $(a[i])}1' file or for different values
awk 'BEGIN{FS=OFS=","; split("n1,n2,n3,...,nm",a); split("value1,value2,...,valuem",v)} {for(i=m;i>0;--i) $(a[i])=v[i] OFS $(a[i])}1' file add a column after each of column n1 < n2 < ... < nm: (start at the back)
awk 'BEGIN{FS=OFS=","; split("n1,n2,n3,...,nm",a)} {for(i=m;i>0;--i) $(a[i])=$(a[i]) OFS new_value}1' file or for different values
awk 'BEGIN{FS=OFS=","; split("n1,n2,n3,...,nm",a); split("value1,value2,...,valuem",v)} {for(i=m;i>0;--i) $(a[i])=$(a[i]) OFS v[i]}1' file 
[help] ;-) .Eventually, you may be get tired of such questions, if not, you're a better person than I am ;-) .And again, a really perfect answer to this problem. Good luck to all.Ok, let's say your csv looks like this:
col1, col2, col3, col4, col5 1, 2, 3, 4, 5 Then, the command:
awk 'BEGIN{FS=OFS=","}{print $1,$2,"new_Col1",$3,"new_Col2",$4,"new_Col5",$5}' t.csv will give the following output:
col1, col2,new_Col1, col3,new_Col2, col4,new_Col5, col5 1, 2,new_Col1, 3,new_Col2, 4,new_Col5, 5 You get the idea? Is that what you want to know?
Even easier to read:
awk '{print $1","$2",new_Col1,"$3",new_Col2,"$4",new_Col5,"$5}' t.csv 
$1contains the 1st column,$2, the 2nd and so on. Good luck and update your question when you're stuck and need additional help