FredFredFred:

What part are you having trouble with? If it's actually removing the data from the file, then a typical method to do it is to write the data you want to keep to a new file. Then rename your data file to a backup version, and rename your new file with the original name.

You're welcome, and good luck.

...roboticus

When your only tool is a hammer, all problems look like your thumb.

hmm, that sounds good, but I have no clue how to do it... Can you provide some code? Thanks

FredFredFred:

# Discard every other line
open FIN, 'INFILE' or die;
open FOUT, '>INFILE.new' or die;
my $cnt;
while (<FIN>) {
   next if $cnt%2;
   print FOUT;
}
close FH;
close FOUT;
rename 'INFILE', 'INFILE.bak';
rename 'INFILE.new', 'INFILE;
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...roboticus

When your only tool is a hammer, all problems look like your thumb.

Please reference the perl documentation for constructs you have trouble with.

$/="\n\n";                    # Set the record separator to be 2 newli
+nes
my $sportfile="my.sport.txt"; # Or whatever the file name is
open (my $sport, "<", $sportfile) or die "Cannot open $sportfile : $!"
+;

while (defined <$sport>){
  next if m/\b$first_name\b.+$last_name\b/;
  print;
}
close $sport;
[download]

This can be directed to a file.

Just don't redirect it to the original file name. The first thing the OS would do is to truncate the original file, leaving no data for your text file to work with.

--MidLifeXis

You are dealing with a database, but making hard work of it. However Perl's DBI module along with DBD::CSV can turn your text based database file into something you can deal with as a "real" database. Consider:

use warnings;
use strict;
use DBI;

unlink 'sports.csv';

my $dbh = DBI->connect("dbi:CSV:f_ext=.csv")
    or die "Cannot connect: $DBI::errstr\n";

$dbh->do("CREATE TABLE sports (name TEXT, sport TEXT)");

my $sth = $dbh->prepare("INSERT INTO sports (name, sport) VALUES (?, ?
+)");

$sth->execute_array({}, [qw(fred joe bob)], [qw(golf hockey luge)]);
dumpTable($dbh);

$dbh->do("DELETE FROM sports WHERE name = 'fred'");
print "\nDeleted fred\n";
dumpTable($dbh);

print "\nCSV file contains:\n";
open my $fIn, '<', 'sports.csv';
print <$fIn>;
close $fIn;


sub dumpTable {
    my ($dbh) = @_;
    my $sql = 'SELECT name, sport FROM sports order by name';

    for my $row (@{$dbh->selectall_arrayref($sql)}) {
        print "$row->[0]: $row->[1]\n";
    }
}
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Prints:

bob: luge
fred: golf
joe: hockey

Deleted fred
bob: luge
joe: hockey

CSV file contains:
name,sport
joe,hockey
bob,luge
[download]

This of course uses a CSV file which may not be what you have, but with a little work you can probably use DBD::AnyData to manage your existing text based data in a very similar fashion.

use strict;
use warnings;
use Tie::File;

my $filename = '/path/to/file.txt';
my $firstname = 'John';
my $lastname = 'Watter';

tie my @array, 'Tie::File', $filename or die $!;
for(my $i = 0; $i <= $#array; $i++){
     if($array[$i] =~ /\b$firstname\b.+\b$lastname\b/){
        splice(@array, --$i, 5);
     }
}
untie @array;
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Alternatively structure/dump the file as a hash (example below), forget all about duplicated blank lines and extra spaces and delete the hash-key provided as argument to the script. You could have a lot of troubles if some lines are duplicated, new fields are added later for new registers, or some fields are missing and you simply delete five untested lines here and there.

my %sports= (
    'johnlazybones' => {
        'firstname' => 'John',
        'lastname' => 'lazybones',
        'sport' => 'none known, never, ever', 
         }, 
     
   'michaelflops' => {
        'firstname' => 'Michael',
        'lastname' => 'flops',
        'sport' => 'sillonball', 
        'victories' => {
            '1' => '01-AUG-2012',
            '2' => '12-SEP-2011',
        },
    },
);
[download]