mirror of
https://git.savannah.gnu.org/git/parallel.git
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263 lines
6.6 KiB
Perl
263 lines
6.6 KiB
Perl
package FileHandle;
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use 5.006;
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use strict;
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our($VERSION, @ISA, @EXPORT, @EXPORT_OK);
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$VERSION = "2.02";
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require IO::File;
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@ISA = qw(IO::File);
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@EXPORT = qw(_IOFBF _IOLBF _IONBF);
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@EXPORT_OK = qw(
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pipe
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autoflush
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output_field_separator
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output_record_separator
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input_record_separator
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input_line_number
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format_page_number
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format_lines_per_page
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format_lines_left
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format_name
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format_top_name
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format_line_break_characters
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format_formfeed
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print
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printf
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getline
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getlines
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);
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#
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# Everything we're willing to export, we must first import.
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#
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import IO::Handle grep { !defined(&$_) } @EXPORT, @EXPORT_OK;
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#
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# Some people call "FileHandle::function", so all the functions
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# that were in the old FileHandle class must be imported, too.
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#
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{
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no strict 'refs';
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my %import = (
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'IO::Handle' =>
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[qw(DESTROY new_from_fd fdopen close fileno getc ungetc gets
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eof flush error clearerr setbuf setvbuf _open_mode_string)],
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'IO::Seekable' =>
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[qw(seek tell getpos setpos)],
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'IO::File' =>
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[qw(new new_tmpfile open)]
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);
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for my $pkg (keys %import) {
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for my $func (@{$import{$pkg}}) {
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my $c = *{"${pkg}::$func"}{CODE}
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or die "${pkg}::$func missing";
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*$func = $c;
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}
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}
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}
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#
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# Specialized importer for Fcntl magic.
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#
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sub import {
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my $pkg = shift;
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my $callpkg = caller;
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require Exporter;
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Exporter::export($pkg, $callpkg, @_);
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#
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# If the Fcntl extension is available,
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# export its constants.
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#
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eval {
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require Fcntl;
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Exporter::export('Fcntl', $callpkg);
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};
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}
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################################################
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# This is the only exported function we define;
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# the rest come from other classes.
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#
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sub pipe {
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my $r = new IO::Handle;
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my $w = new IO::Handle;
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CORE::pipe($r, $w) or return undef;
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($r, $w);
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}
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# Rebless standard file handles
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bless *STDIN{IO}, "FileHandle" if ref *STDIN{IO} eq "IO::Handle";
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bless *STDOUT{IO}, "FileHandle" if ref *STDOUT{IO} eq "IO::Handle";
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bless *STDERR{IO}, "FileHandle" if ref *STDERR{IO} eq "IO::Handle";
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1;
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__END__
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=head1 NAME
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FileHandle - supply object methods for filehandles
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=head1 SYNOPSIS
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use FileHandle;
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$fh = FileHandle->new;
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if ($fh->open("< file")) {
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print <$fh>;
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$fh->close;
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}
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$fh = FileHandle->new("> FOO");
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if (defined $fh) {
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print $fh "bar\n";
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$fh->close;
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}
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$fh = FileHandle->new("file", "r");
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if (defined $fh) {
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print <$fh>;
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undef $fh; # automatically closes the file
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}
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$fh = FileHandle->new("file", O_WRONLY|O_APPEND);
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if (defined $fh) {
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print $fh "corge\n";
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undef $fh; # automatically closes the file
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}
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$pos = $fh->getpos;
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$fh->setpos($pos);
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$fh->setvbuf($buffer_var, _IOLBF, 1024);
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($readfh, $writefh) = FileHandle::pipe;
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autoflush STDOUT 1;
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=head1 DESCRIPTION
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NOTE: This class is now a front-end to the IO::* classes.
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C<FileHandle::new> creates a C<FileHandle>, which is a reference to a
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newly created symbol (see the C<Symbol> package). If it receives any
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parameters, they are passed to C<FileHandle::open>; if the open fails,
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the C<FileHandle> object is destroyed. Otherwise, it is returned to
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the caller.
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C<FileHandle::new_from_fd> creates a C<FileHandle> like C<new> does.
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It requires two parameters, which are passed to C<FileHandle::fdopen>;
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if the fdopen fails, the C<FileHandle> object is destroyed.
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Otherwise, it is returned to the caller.
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C<FileHandle::open> accepts one parameter or two. With one parameter,
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it is just a front end for the built-in C<open> function. With two
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parameters, the first parameter is a filename that may include
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whitespace or other special characters, and the second parameter is
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the open mode, optionally followed by a file permission value.
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If C<FileHandle::open> receives a Perl mode string (">", "+<", etc.)
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or a POSIX fopen() mode string ("w", "r+", etc.), it uses the basic
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Perl C<open> operator.
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If C<FileHandle::open> is given a numeric mode, it passes that mode
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and the optional permissions value to the Perl C<sysopen> operator.
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For convenience, C<FileHandle::import> tries to import the O_XXX
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constants from the Fcntl module. If dynamic loading is not available,
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this may fail, but the rest of FileHandle will still work.
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C<FileHandle::fdopen> is like C<open> except that its first parameter
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is not a filename but rather a file handle name, a FileHandle object,
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or a file descriptor number.
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If the C functions fgetpos() and fsetpos() are available, then
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C<FileHandle::getpos> returns an opaque value that represents the
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current position of the FileHandle, and C<FileHandle::setpos> uses
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that value to return to a previously visited position.
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If the C function setvbuf() is available, then C<FileHandle::setvbuf>
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sets the buffering policy for the FileHandle. The calling sequence
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for the Perl function is the same as its C counterpart, including the
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macros C<_IOFBF>, C<_IOLBF>, and C<_IONBF>, except that the buffer
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parameter specifies a scalar variable to use as a buffer. WARNING: A
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variable used as a buffer by C<FileHandle::setvbuf> must not be
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modified in any way until the FileHandle is closed or until
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C<FileHandle::setvbuf> is called again, or memory corruption may
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result!
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See L<perlfunc> for complete descriptions of each of the following
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supported C<FileHandle> methods, which are just front ends for the
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corresponding built-in functions:
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close
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fileno
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getc
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gets
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eof
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clearerr
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seek
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tell
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See L<perlvar> for complete descriptions of each of the following
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supported C<FileHandle> methods:
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autoflush
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output_field_separator
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output_record_separator
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input_record_separator
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input_line_number
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format_page_number
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format_lines_per_page
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format_lines_left
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format_name
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format_top_name
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format_line_break_characters
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format_formfeed
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Furthermore, for doing normal I/O you might need these:
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=over 4
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=item $fh->print
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See L<perlfunc/print>.
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=item $fh->printf
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See L<perlfunc/printf>.
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=item $fh->getline
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This works like <$fh> described in L<perlop/"I/O Operators">
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except that it's more readable and can be safely called in a
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list context but still returns just one line.
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=item $fh->getlines
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This works like <$fh> when called in a list context to
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read all the remaining lines in a file, except that it's more readable.
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It will also croak() if accidentally called in a scalar context.
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=back
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There are many other functions available since FileHandle is descended
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from IO::File, IO::Seekable, and IO::Handle. Please see those
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respective pages for documentation on more functions.
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=head1 SEE ALSO
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The B<IO> extension,
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L<perlfunc>,
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L<perlop/"I/O Operators">.
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=cut
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