Shell Programming and Scripting

 
sed '1s/^[^,]*,//' file.csv

sed -e '1s/^[^,]*,//' -e '1s/$/,10/' file

#  echo "0,0,0,0,1,0,1,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0" | sed -e '1s/^[^,]*,//' -e '1s/$/,10/'
0,0,0,1,0,1,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,10

-bash-3.00$ ./parse.pl -l 5 -v 300
-bash-3.00$ ./parse.pl -d -l 5 -v 300
input:
 41,18,27,9,27,41,59,20,27,54,63,34,28,43,40,131,7,8,19,0,62,16,30,23,25,3,4,9,24,12,19
output:
 18,27,9,27,41,59,20,27,54,63,34,28,43,40,131,7,8,19,0,62,16,30,23,25,3,4,9,24,12,19,300

#!/usr/bin/perl -w

################################################################################
# Pragma
use strict;
use Getopt::Std;
use vars qw/ %opt /;

################################################################################
# Forward declaration of subroutines
sub do_init();

################################################################################
# Variable declaration
my $input = "./file";
my $output = "./file.output";
my @entireList;
my $entireList;
my $listLineNumber;
my @oneLine;
my $newLine;
my $line;
my $DEBUG;

################################################################################
# You don't need to get your command line variables this way
#   - it's a habit that I got into, and it works for me - your mileage may vary
do_init();

# set DEBUG flag according to command line options
if ( $opt{d} )
{
   $DEBUG = 1;
}
else
{
   $DEBUG = 0;
}

################################################################################
# Begin the MAIN portion of the script
################################################################################

# Open your input file and place the contents into the array @entireList
# - each line is a separate element in the array
open(FILE, "<$input") or die "Cannot open $input for read :$!";
chomp (@entireList = <FILE>);
close( FILE );

# I haven't really added any error checking for the options. If you don't
# assign a line item or value, the script will still run - it won't substitute
# unless you provide -l <linenumber> AND -v <value>

if ( $opt{l} && $opt{v} )
{
   $listLineNumber = $opt{l};
   # split string (one line) into a temporary array
   print "input:\n $entireList[$listLineNumber]\n" if $DEBUG;
   @oneLine = split(/,/, $entireList[$listLineNumber]);
   shift @oneLine;
   push @oneLine, $opt{v};
   # put array back into a string - and back into the original array
   $entireList[$listLineNumber] = join(",",@oneLine);
   print "output:\n $entireList[$listLineNumber]\n" if $DEBUG;
}

# Write the file - here I have it writing to a new file - you can have it
# overwrite the original file if you prefer - simply change the variable
# declaration at the top for $output to match $input - or change the code
# below to use $input instead of $output. I recommend changing this in the
# variable declaration - so that you can reuse the script later
open(FILE2, ">$output") or die "Cannot open $output for read :$!";
foreach $line(@entireList)
{
   print FILE2 "$line\n";
}
close( FILE2 );


################################################################################
# Standard handling message - maybe too much for simple utilities - oh well... #
################################################################################
sub do_init()
{
   my $opt_string = 'dhl:v:';
   getopts( "$opt_string", \%opt ) or do_usage();
   do_usage() if $opt{h};
}
sub do_usage()
{
   print "\nusage: $0 [-h] [-l {line number}] [-n {new value}]\n\n";
   exit;
}