transform csv file using awk script - bash

Question

I have csv file as below:
C1, C2, C3,Cv1,Cv2,Cv3,Cv4 ... this one can be have longer column
x1, x2 ,x3.1, 1.1, 1.2, 1.3, 1.4
x1, x2, x3.2, 2.1, 2.2, 2.3, 2.4
x1, x2, x3.3, 3.1, 3.2, 3.3, 3.4
i would like to transform this csv file to as below:
C1,C2, C3,CTEXT,XVALUE
x1, x2, x3.1, Cv1 , 1.1
x1, x2, x3.1, Cv2 , 1.2
x1, x2, x3.1, Cv3 , 1.3
x1, x2, x3.1, Cv4 , 1.4
x1, x2, x3.2, Cv1 , 2.1
x1, x2, x3.2, Cv2 , 2.2
x1, x2, x3.2, Cv3 , 2.3
x1, x2, x3.2, Cv4 , 2.4
x1, x2, x3.3, Cv1 , 3.1
x1,x2,x3.3, Cv2 , 3.2
x1,x2,x3.3, Cv3 , 3.3
x1,x2,x3.3, Cv4 , 3.4
Below is my code:
#!/bin/bash
awk -F, -v OFS=, '{ if (NR==1)
{ print $1,$2,$3, "CTEXT","XVALUE"
i=4; while (i < NF) {
a[i]=$i; i=i+1
}
am=NF; next
}
i=4 ; while (i < am) {
if (i > NF) {print "record "NR" insufficient value" >/dev/stderr
break}
print $1,$2,$3,a[i],$i
i=i+1
}
if (am <NF) print "record "NR" too many values for text" >/dev/stderr
}' input.csv
When i run the script, it shows error :
awk: syntax error near line 2
awk: bailing out near line 2
Edit by Ed Morton - I just ran the script through a beautifier (gawk -o- '...') so it's much easier to read/understand:
{
if (NR == 1) {
print $1, $2, $3, "CTEXT", "XVALUE"
i = 4
while (i < NF) {
a[i] = $i
i = i + 1
}
am = NF
next
}
i = 4
while (i < am) {
if (i > NF) {
print("record " NR " insufficient value") > (/dev/) stderr
break
}
print $1, $2, $3, a[i], $i
i = i + 1
}
if (am < NF) {
print("record " NR " too many values for text") > (/dev/) stderr
}
}

Answer 1

Even if you switch your Solaris awk to gawk or nawk, there still
remain some problems. Would you please try the following:
awk -F, -v OFS=, '
NR==1 {
print $1,$2,$3, "CTEXT","XVALUE"
for (i = 4; i <= NF; i++) a[i]=$i
am=NF; next
}
{
if (am < NF) {
print "record "NR" too many values for text" > "/dev/stderr"
next
}
for (i = 4; i <= am; i++) {
if (i > NF) {
print "record "NR" insufficient value" > "/dev/stderr"
break
}
print $1,$2,$3,a[i],$i
}
}' input.csv
You need to increment i up to NR or am (not < but <=).
Enclose /dev/stderr with quotes.
Better to use for loop rather than while.
Hope this helps.

Answer 2

something like this
$ awk -F, 'BEGIN {OFS=FS}
NR==1 {n=split($0,h);
print $1,$2,$3,"CTEXT","XVALUE";
next}
n!=NF {print n<NF?"too many":"not enough";
exit}
{for(i=4;i<=NF;i++) print $1,$2,$3,h[i],$i}' file
C1,C2,C3,CTEXT,XVALUE
x1,x2,x3.1,Cv1,1.1
x1,x2,x3.1,Cv2,1.2
x1,x2,x3.1,Cv3,1.3
x1,x2,x3.1,Cv4,1.4
x1,x2,x3.2,Cv1,2.1
x1,x2,x3.2,Cv2,2.2
x1,x2,x3.2,Cv3,2.3
x1,x2,x3.2,Cv4,2.4
x1,x2,x3.3,Cv1,3.1
x1,x2,x3.3,Cv2,3.2
x1,x2,x3.3,Cv3,3.3
x1,x2,x3.3,Cv4,3.4