loody <[EMAIL PROTECTED]> asked:
> I try to read the last line of a file directly instead of using
> while(<>) or something else to read each line until "undef"
> bumped to me.
> If you know some build-in functions or another modules for me
> to use, please help me.
Off the top of my head:
#!/usr/bin/perl -w
use strict;
use Fcntl qw(SEEK_END);
my $file = 'somefile.txt';
open( IN, '<', $file ) or die "Can't open '$file': $!";
my $size = -s $file;
my $found;
my $offset = 256;
while( ! defined( $found ) ){
# prevent seek from overshooting the start of the file.
$offset = $size if $offset > $size;
seek( IN, -$offset, SEEK_END ) or warn "seek failed: $!";
# read line(s) from filehandle. Ideally, offset was chosen
# such that @lines contains part of the penultimate line
# and the last line.
my @lines = <IN>;
if( @lines > 1 ){
# more than one lines means we can be sure we do have the last one.
$found = $lines[ -1 ];
} elsif( $offset >= $size ) {
# if we have read the whole file and it's just one line, then that is the
last line.
$found = $lines[ 0 ];
} else {
# try again with a bigger offset
$offset += 256;
}
}
print "The last line is: $found\n";
__END__
HTH,
Thomas
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