Shell Programming and Scripting

$ cat csv.awk
function csv2array ()
{
        gsub(DELIM, REPL)
        $0 = gensub(/([^,])\"\"/, "\\1'", "g")
        out = ""
        n = length($0)
        for (i = 1;  i <= n;  i++) {
                if ((ch = substr($0, i, 1)) == "\"") {
                        inString = (inString) ? 0 : 1
                }
                out = out ((ch == "," && ! inString) ? DELIM : ch)
        }
        csvNumFields=split(out,csvFields,DELIM);
}
 
BEGIN {
        if (DELIM == "") DELIM = "\t"
        if (REPL == "") REPL = "~"
}
{
        csv2array();
 
        if (csvNumFields < 4) {
                for (i=1; i<=csvNumFields; i++) {
                        if (i>1) {
                                printf (",");
                        }
                        printf ("%s", csvFields[i]);
                }
                printf ("\n");
        }
}
$ cat 1.txt
a,b,c,d
1,2,3
4
a,"h93,23",c,d
a,"h94,24",c
d
a,"h96,24",c
d
a,"h95,23",c,d
 
$ awk -f csv.awk 1.txt
1,2,3
4
a,"h94,24",c
d
a,"h96,24",c
d