update-csv.pl

#!/usr/bin/perl

use strict;
use warnings; 
use Text::CSV;

my $tenantColumn = 1;
my $outputFile = "output.csv";


my $inputCsv = Text::CSV->new({ })
    or die "Cannot use Text::CSV ($!)";


my $outputCsv = Text::CSV->new({eol => $/ })
    or die "Cannot use Text::CSV ($!)";


my $inputFile = $ARGV[0]
    or die "Need to get CSV file on the command line\n";


open(my $dataIn, '<', $inputFile)
    or die "Could not open '$inputFile' $!\n";

open my $dataOut, '>', $outputFile
    or die "Cannot open $outputFile ($!)";

my $lineNumber = 0;
while (my $line = <$dataIn>) {
  chomp $line;
 
  if ($inputCsv->parse($line)) {
    my @fields = $inputCsv->fields();

    if($lineNumber > 0){
        $fields[$tenantColumn] = "my tenant" ;
    }

    $outputCsv->print($dataOut, \@fields);
    $lineNumber++;
  } else {
      warn "Line could not be parsed: $line\n";
  }
}

close $dataOut
    or die "Failed to close $outputFile ($!)";