I want to replace all commas between the 13th comma starting from left and 12th comma starting from right in Unix - unix

Question

Present
1856292496,-1863203096,302,918468087151,808648712,405670043170066,919015026101,M,6,T,0,15,2c,Dear Customer, Your Request is under Process,03,11/05/2017 10:00:00,11/05/2017 10:00:00,11/,11/05/2017 10:00:00,0,03,,255,,333,ERecharge_RCOM,919015540301
Requirement
1856292496,-1863203096,302,918468087151,808648712,405670043170066,919015026101,M,6,T,0,15,2c,Dear Customer Your Request is under Process,03,11/05/2017 10:00:00,11/05/2017 10:00:00,11/,11/05/2017 10:00:00,0,03,,255,,333,ERecharge_RCOM,919015540301
Current
1856292499,-1863203087,301,918081224379,808648711,405540046666191,919026240102,M,6,T,0,15,8d,Dear Business Partner,your current Core balance is Rs.29.8,GSM balance is Rs.12892.14,MRCOM balance is Rs.1 and MRTL balance is Rs.1.Reliance,03,11/05/2017 10:00:00,11/05/2017 10:00:00,11/,11/05/2017 10:00:00,0,01,,255,,333,BalQuery_RCOM,919835853611
Requirement
1856292499,-1863203087,301,918081224379,808648711,405540046666191,919026240102,M,6,T,0,15,8d,Dear Business Partner your current Core balance is Rs.29.8 GSM balance is Rs.12892.14 MRCOM balance is Rs.1 and MRTL balance is Rs.1.Reliance,03,11/05/2017 10:00:00,11/05/2017 10:00:00,11/,11/05/2017 10:00:00,0,01,,255,,333,BalQuery_RCOM,919835853611
I need to replace all the commas between the 13th comma from the left to the 12th comma starting from the right with a space, on a Unix system.

Answer 1

Here's a moderately succinct but mostly inscrutable (if not incomprehensible) solution using Perl.
#!/usr/bin/perl -anlF,
use strict;
use warnings;
my $lhs = 13;
my $rhs = 13;
$, = ","; # Perl is obscure on occasion!
my($nflds) = scalar(#F);
print #F[0 .. $lhs-1], "#F[$lhs .. $nflds-$rhs-1]", #F[$nflds-$rhs .. $nflds-1]
if ($nflds > $lhs + $rhs);
The shebang line uses -l to make Perl handle newlines automatically. See perldoc perlrun.
It also uses -F, which, in Perl 5.20.0 and later, is explicitly documented to automatically put Perl into -a (awk) mode and -n (read loop but don't print) mode. The input lines are automatically split into the array F using , as the delimiter. Earlier versions of Perl do not infer -a and -n from the presence of -F, so the code (now) uses -an as well as -F,. The updated code has been shown to work with Perl 5.10.0 and with each major release up to 5.18, as well as 5.20 and later.
The use strict; and use warnings; lines set Perl to fussy. You should always use them.
The two assignments set up the values you specified in the question, except that it seems to be the 13th field from the right, rather than the 12th, that you want combined. They're easily fungible if you need to.
The $, = ","; lines sets the output field separator (OFS in Awk, and $OFS in Perl under use English qw( -no_match_vars );). See perldoc English and perldoc perlvars.
The my($nflds) = scalar(#F); line determines the number of fields.
The print line is conditional on there being enough fields.
It uses Perl's array slices to:
print fields 0..$lhs-1 as separate comma-separated fields
combine fields $lhs..$nflds-$rhs-1 as a single space-separated field (by virtue of the string around the slice)
print fields $nflds-$rhs..$nflds-1 as separate comma-separated fields
The output from that, given your input data, is:
1856292496,-1863203096,302,918468087151,808648712,405670043170066,919015026101,M,6,T,0,15,2c,Dear Customer Your Request is under Process,03,11/05/2017 10:00:00,11/05/2017 10:00:00,11/,11/05/2017 10:00:00,0,03,,255,,333,ERecharge_RCOM,919015540301
1856292499,-1863203087,301,918081224379,808648711,405540046666191,919026240102,M,6,T,0,15,8d,Dear Business Partner your current Core balance is Rs.29.8 GSM balance is Rs.12892.14 MRCOM balance is Rs.1 and MRTL balance is Rs.1.Reliance,03,11/05/2017 10:00:00,11/05/2017 10:00:00,11/,11/05/2017 10:00:00,0,01,,255,,333,BalQuery_RCOM,919835853611
Note that the leading space on one of the fields in the first line is preserved.
I didn't come up with that immediately. I generated a more verbose solution like this, first:
#!/usr/bin/env perl -l
use strict;
use warnings;
my $lhs = 13;
my $rhs = 13;
while (<>)
{
chomp;
my(#fields) = split /,/;
my($nflds) = scalar(#fields);
my(#output) = #fields;
if ($nflds > $lhs + $rhs)
{
my(#combine) = #fields[$lhs .. $nflds-$rhs-1];
my $composite = "#combine";
#output = (#fields[0 .. $lhs-1], $composite, #fields[$nflds-$rhs .. $nflds-1]);
}
local $, = ",";
print #output;
}
This produces the same output as the other script. I had the scripts called rs13.pl (verbose) and rs17.pl (compact) and checked them like this (data contains your two lines of input data):
diff <(perl rs13.pl data) <(perl rs17.pl data)
There was no difference.
There are ways to make the compact solution more compact, but I'm not sure they help much.
Here is another version that uses the splice and join functions instead of array slices. In some ways, it is tidier than the other two, but it doesn't have the same protection against lines with too few fields in them.
#!/usr/bin/perl -anlF,
use strict;
use warnings;
my $lhs = 13;
my $rhs = 13;
$, = ","; # Perl is obscure on occasion!
my($nflds) = scalar(#F);
splice(#F, $lhs, $nflds - $lhs - $rhs, join(' ', #F[$lhs .. $nflds-$rhs-1]));
print #F;
It produces the same result as the other two scripts.
Yes, you could write the code in Awk; it wouldn't be as compact as this.