Shell Programming and Scripting

data1,value1,value2
data1,value3,value2
data1,value5,value6

data2,value1,value2
data2,value3,value4

data3,value1,value2
data3,value3,value4

data4,value1,value2
data4,value3,value4
data4,value5,value6

data1,value1,value3,value5,value2,value4,value6
data2,value1,value3,value2,value4
data3,value1,value3,value2,value4
data4,value1,value3,value5,value2,value4,value6

d={}
for line in open("file"):
    line=line.strip().split(",")
    d.setdefault(line[0],[])
    d[line[0]].extend(line[1:])
for i,j in d.iteritems():
    if i != "":print i,','.join(j)

# ./test.py
data4 value1,value2,value3,value4,value5,value6
data1 value1,value2,value3,value2,value5,value6
data3 value1,value2,value3,value4
data2 value1,value2,value3,value4

nawk -F"," '{
if (_[$1]=="")
	_[$1]=sprintf("%s,%s",$2,$3)
else
	_[$1]=sprintf("%s,%s,%s",_[$1],$2,$3)
}
END{
for(i in _){
	num=split(_[i],arr,",")
	n=num/2
	printf i","
	for(j=1;j<=2;j++)
		for(k=1;k<=n;k++)
				printf arr[j+2*(k-1)]","		
	print ""
}
}' a.txt | sed 's/,$//'

open $fh,"<","a.txt";
while(<$fh>){
	chomp;
	my @tmp=split(",",$_);
	push @{$hash{$tmp[0]}->{1}},$tmp[1];
	push @{$hash{$tmp[0]}->{2}},$tmp[2];
}
foreach $key(keys %hash){
	print $key,",";
	print join ",",@{$hash{$key}->{1}};
	print ",";
	print join ",",@{$hash{$key}->{2}};
	print "\n";
}