Shell Programming and Scripting

I have to create a single file from three files, Please see below for samples:

day.txt
20090101
20090102

item.txt
123456789101
12345678910209
1234567891

str.txt
1
12
123

output.txt
20090101123456789101 1 0
2009010112345678910209 12 0
200901011234567891 123 0
20090101123456789101 1 0
2009010112345678910209 12 0
200901011234567891 123 0
20090101123456789101 1 0
2009010112345678910209 12 0
200901011234567891 123 0
20090102123456789101 1 0
2009010212345678910209 12 0
200901021234567891 123 0
20090102123456789101 1 0
2009010212345678910209 12 0
200901021234567891 123 0
20090102123456789101 1 0
2009010212345678910209 12 0
200901021234567891 123 0

output should be:
1.Cartesian join of all item stores day
2.Date would occupy characters 1-8.
2.Item would occupy characters 9-28.If the characters are not enough to make 20 characters, pad it with space.
3.Str would occupy character 29-48.If the characters are not enough to make 20 characters, pad it with space.
4.The 49th character of the line would always be zero.

---------- Post updated at 05:30 PM ---------- Previous update was at 05:18 PM ----------

the output file was not diplayed correctly, the white spaces between the fields was truncated to a single space.

day.txt has only 2 records!?

try if it works,

Code:

/home->cat day.txt 
20090101
20090102
20090102
/home->cat item.txt 
123456789101
12345678910209
1234567891
/home->cat str.txt 
1
12
123
/home->while read line; do printf "%-20d\n" $line;done< item.txt > item.tmp
/home->while read line; do printf "%-20d 0\n" $line;done< str.txt > str.tmp
/home->paste -d '' day.txt item.tmp | paste -d ' ' - str.tmp > outfile.txt
/home->rm item.tmp str.tmp
/home->cat outfile.txt
20090101123456789101         1                    0
2009010212345678910209       12                   0
200901021234567891           123                  0
/home->

I expect an awk solution which would be simpler.

Code:

#!/usr/bin/perl
use warnings;
my (@day,@item,@str);

open(DAY,"day.txt") || die "can't open file:$!";
open(ITEM,"item.txt") || die "can't open file:$!";
open(STR,"str.txt") || die "can't open file:$!";

@day=<DAY>;
@item=<ITEM>;
@str=<STR>;
map(chomp,@day);
map(chomp,@item);
map(chomp,@str);
my $dlen=@day;
my $ilen=@item;
my $slen=@str;
close(DAY);
close(ITEM);
close(STR);

print "$dlen:$ilen:$slen\n";

for($i=0;$i<$dlen;$i++)
 {
   for($j=0;$j<$ilen;$j++)
    {
    for ($k=0;$k<$slen;$k++)
      {
       printf("%-8s%20s%20s%3s\n",$day[$i],$item[$j],$str[$k],"0");
      }
   }
 }

cheers,
Devaraj Takhellambam