phpman > perldoc > File::Slurp(3pm)

NAME
    File::Slurp - Simple and Efficient Reading/Writing/Modifying of Complete Files

SYNOPSIS
      use File::Slurp;

      # read in a whole file into a scalar
      my $text = read_file('/path/file');

      # read in a whole file into an array of lines
      my @lines = read_file('/path/file');

      # write out a whole file from a scalar
      write_file('/path/file', $text);

      # write out a whole file from an array of lines
      write_file('/path/file', @lines);

      # Here is a simple and fast way to load and save a simple config file
      # made of key=value lines.
      my %conf = read_file('/path/file') =~ /^(\w+)=(.*)$/mg;
      write_file('/path/file', {atomic => 1}, map "$_=$conf{$_}\n", keys %conf);

      # insert text at the beginning of a file
      prepend_file('/path/file', $text);

      # in-place edit to replace all 'foo' with 'bar' in file
      edit_file { s/foo/bar/g } '/path/file';

      # in-place edit to delete all lines with 'foo' from file
      edit_file_lines sub { $_ = '' if /foo/ }, '/path/file';

      # read in a whole directory of file names (skipping . and ..)
      my @files = read_dir('/path/to/dir');

DESCRIPTION
    This module provides subs that allow you to read or write entire files with one simple call.
    They are designed to be simple to use, have flexible ways to pass in or get the file contents
    and to be very efficient. There is also a sub to read in all the files in a directory.

  WARNING - PENDING DOOM
    Although you technically *can*, do NOT use this module to work on file handles, pipes, sockets,
    standard IO, or the "DATA" handle. These are features implemented long ago that just really
    shouldn't be abused here.

    Be warned: this activity will lead to inaccurate encoding/decoding of data.

    All further mentions of actions on the above have been removed from this documentation and that
    feature set will likely be deprecated in the future.

    In other words, if you don't have a filename to pass, consider using the standard "do { local
    $/; <$fh> }", or Data::Section/Data::Section::Simple for working with "__DATA__".

FUNCTIONS
    File::Slurp implements the following functions.

  append_file
            use File::Slurp qw(append_file write_file);
            my $res = append_file('/path/file', "Some text");
            # same as
            my $res = write_file('/path/file', {append => 1}, "Some text");

    The "append_file" function is simply a synonym for the "write_file" in File::Slurp function, but
    ensures that the "append" option is set.

  edit_file
            use File::Slurp qw(edit_file);
            # perl -0777 -pi -e 's/foo/bar/g' /path/file
            edit_file { s/foo/bar/g } '/path/file';
            edit_file sub { s/foo/bar/g }, '/path/file';
            sub replace_foo { s/foo/bar/g }
            edit_file \&replace_foo, '/path/file';

    The "edit_file" function reads in a file into $_, executes a code block that should modify $_,
    and then writes $_ back to the file. The "edit_file" function reads in the entire file and calls
    the code block one time. It is equivalent to the "-pi" command line options of Perl but you can
    call it from inside your program and not have to fork out a process.

    The first argument to "edit_file" is a code block or a code reference. The code block is not
    followed by a comma (as with "grep" and "map") but a code reference is followed by a comma.

    The next argument is the filename.

    The next argument(s) is either a hash reference or a flattened hash, "key => value" pairs. The
    options are passed through to the "write_file" in File::Slurp function. All options are
    described there. Only the "binmode" and "err_mode" options are supported. The call to
    "write_file" in File::Slurp has the "atomic" option set so you will always have a consistent
    file.

  edit_file_lines
            use File::Slurp qw(edit_file_lines);
            # perl -pi -e '$_ = "" if /foo/' /path/file
            edit_file_lines { $_ = '' if /foo/ } '/path/file';
            edit_file_lines sub { $_ = '' if /foo/ }, '/path/file';
            sub delete_foo { $_ = '' if /foo/ }
            edit_file \&delete_foo, '/path/file';

    The "edit_file_lines" function reads each line of a file into $_, and executes a code block that
    should modify $_. It will then write $_ back to the file. It is equivalent to the "-pi" command
    line options of Perl but you can call it from inside your program and not have to fork out a
    process.

    The first argument to "edit_file_lines" is a code block or a code reference. The code block is
    not followed by a comma (as with "grep" and "map") but a code reference is followed by a comma.

    The next argument is the filename.

    The next argument(s) is either a hash reference or a flattened hash, "key => value" pairs. The
    options are passed through to the "write_file" in File::Slurp function. All options are
    described there. Only the "binmode" and "err_mode" options are supported. The call to
    "write_file" in File::Slurp has the "atomic" option set so you will always have a consistent
    file.

  ef
            use File::Slurp qw(ef);
            # perl -0777 -pi -e 's/foo/bar/g' /path/file
            ef { s/foo/bar/g } '/path/file';
            ef sub { s/foo/bar/g }, '/path/file';
            sub replace_foo { s/foo/bar/g }
            ef \&replace_foo, '/path/file';

    The "ef" function is simply a synonym for the "edit_file" in File::Slurp function.

  efl
            use File::Slurp qw(efl);
            # perl -pi -e '$_ = "" if /foo/' /path/file
            efl { $_ = '' if /foo/ } '/path/file';
            efl sub { $_ = '' if /foo/ }, '/path/file';
            sub delete_foo { $_ = '' if /foo/ }
            efl \&delete_foo, '/path/file';

    The "efl" function is simply a synonym for the "edit_file_lines" in File::Slurp function.

  overwrite_file
            use File::Slurp qw(overwrite_file);
            my $res = overwrite_file('/path/file', "Some text");

    The "overwrite_file" function is simply a synonym for the "write_file" in File::Slurp function.

  prepend_file
            use File::Slurp qw(prepend_file);
            prepend_file('/path/file', $header);
            prepend_file('/path/file', \@lines);
            prepend_file('/path/file', { binmode => ':raw'}, $bin_data);

            # equivalent to:
            use File::Slurp qw(read_file write_file);
            my $content = read_file('/path/file');
            my $new_content = "hahahaha";
            write_file('/path/file', $new_content . $content);

    The "prepend_file" function is the opposite of "append_file" in File::Slurp as it writes new
    contents to the beginning of the file instead of the end. It is a combination of "read_file" in
    File::Slurp and "write_file" in File::Slurp. It works by first using "read_file" to slurp in the
    file and then calling "write_file" with the new data and the existing file data.

    The first argument to "prepend_file" is the filename.

    The next argument(s) is either a hash reference or a flattened hash, "key => value" pairs. The
    options are passed through to the "write_file" in File::Slurp function. All options are
    described there.

    Only the "binmode" and "err_mode" options are supported. The "write_file" call has the "atomic"
    option set so you will always have a consistent file.

  read_dir
            use File::Slurp qw(read_dir);
            my @files = read_dir('/path/to/dir');
            # all files, even the dots
            my @files = read_dir('/path/to/dir', keep_dot_dot => 1);
            # keep the full file path
            my @paths = read_dir('/path/to/dir', prefix => 1);
            # scalar context
            my $files_ref = read_dir('/path/to/dir');

    This function returns a list of the filenames in the supplied directory. In list context, an
    array is returned, in scalar context, an array reference is returned.

    The first argument is the path to the directory to read.

    The next argument(s) is either a hash reference or a flattened hash, "key => value" pairs. The
    following options are available:

    *   err_mode

        The "err_mode" option has three possible values: "quiet", "carp", or the default, "croak".
        In "quiet" mode, all errors will be silent. In "carp" mode, all errors will be emitted as
        warnings. And, in "croak" mode, all errors will be emitted as exceptions. Take a look at
        Try::Tiny or Syntax::Keyword::Try to see how to catch exceptions.

    *   keep_dot_dot

        The "keep_dot_dot" option is a boolean option, defaulted to false (0). Setting this option
        to true (1) will also return the "." and ".." files that are removed from the file list by
        default.

    *   prefix

        The "prefix" option is a boolean option, defaulted to false (0). Setting this option to true
        (1) add the directory as a prefix to the file. The directory and the filename are joined
        using "File::Spec->catfile()" to ensure the proper directory separator is used for your OS.
        See File::Spec.

  read_file
            use File::Slurp qw(read_file);
            my $text = read_file('/path/file');
            my $bin = read_file('/path/file', { binmode => ':raw' });
            my @lines = read_file('/path/file');
            my $lines_ref = read_file('/path/file', array_ref => 1);
            my $lines_ref = [ read_file('/path/file') ];

            # or we can read into a buffer:
            my $buffer;
            read_file('/path/file', buf_ref => \$buffer);

            # or we can set the block size for the read
            my $text_ref = read_file('/path/file', blk_size => 10_000_000, array_ref => 1);

            # or we can get a scalar reference
            my $text_ref = read_file('/path/file', scalar_ref => 1);

    This function reads in an entire file and returns its contents to the caller. In scalar context
    it returns the entire file as a single scalar. In list context it will return a list of lines
    (using the current value of $/ as the separator, including support for paragraph mode when it is
    set to '').

    The first argument is the path to the file to be slurped in.

    The next argument(s) is either a hash reference or a flattened hash, "key => value" pairs. The
    following options are available:

    *   array_ref

        The "array_ref" option is a boolean option, defaulted to false (0). Setting this option to
        true (1) will only have relevance if the "read_file" function is called in scalar context.
        When true, the "read_file" function will return a reference to an array of the lines in the
        file.

    *   binmode

        The "binmode" option is a string option, defaulted to empty (''). If you set the "binmode"
        option, then its value is passed to a call to "binmode" on the opened handle. You can use
        this to set the file to be read in binary mode, utf8, etc. See "perldoc -f binmode" for
        more.

        Please note that using binmode :utf8 with sysread (and thus read_file) has been deprecated
        in recent versions of perl.

    *   blk_size

        You can use this option to set the block size used when slurping from an already open handle
        (like "\*STDIN"). It defaults to 1MB.

    *   buf_ref

        The "buf_ref" option can be used in conjunction with any of the other options. You can use
        this option to pass in a scalar reference and the slurped file contents will be stored in
        the scalar. This saves an extra copy of the slurped file and can lower RAM usage vs
        returning the file. It is usually the fastest way to read a file into a scalar.

    *   chomp

        The "chomp" option is a boolean option, defaulted to false (0). Setting this option to true
        (1) will cause each line to have its contents "chomp"ed. This option works in list context
        or in scalar context with the "array_ref" option.

    *   err_mode

        The "err_mode" option has three possible values: "quiet", "carp", or the default, "croak".
        In "quiet" mode, all errors will be silent. In "carp" mode, all errors will be emitted as
        warnings. And, in "croak" mode, all errors will be emitted as exceptions. Take a look at
        Try::Tiny or Syntax::Keyword::Try to see how to catch exceptions.

    *   scalar_ref

        The "scalar_ref" option is a boolean option, defaulted to false (0). It only has meaning in
        scalar context. The return value will be a scalar reference to a string which is the
        contents of the slurped file. This will usually be faster than returning the plain scalar.
        It will also save memory as it will not make a copy of the file to return.

  rf
            use File::Slurp qw(rf);
            my $text = rf('/path/file');

    The "rf" function is simply a synonym for the "read_file" in File::Slurp function.

  slurp
            use File::Slurp qw(slurp);
            my $text = slurp('/path/file');

    The "slurp" function is simply a synonym for the "read_file" in File::Slurp function.

  wf
            use File::Slurp qw(wf);
            my $res = wf('/path/file', "Some text");

    The "wf" function is simply a synonym for the "write_file" in File::Slurp function.

  write_file
            use File::Slurp qw(write_file);
            write_file('/path/file', @data);
            write_file('/path/file', {append => 1}, @data);
            write_file('/path/file', {binmode => ':raw'}, $buffer);
            write_file('/path/file', \$buffer);
            write_file('/path/file', $buffer);
            write_file('/path/file', \@lines);
            write_file('/path/file', @lines);

            # binmode
            write_file('/path/file', {binmode => ':raw'}, @data);
            write_file('/path/file', {binmode => ':utf8'}, $utf_text);

            # buffered
            write_file('/path/file', {buf_ref => \$buffer});
            write_file('/path/file', \$buffer);
            write_file('/path/file', $buffer);

            # append
            write_file('/path/file', {append => 1}, @data);

            # no clobbering
            write_file('/path/file', {no_clobber => 1}, @data);

    This function writes out an entire file in one call. By default "write_file" returns 1 upon
    successfully writing the file or "undef" if it encountered an error. You can change how errors
    are handled with the "err_mode" option.

    The first argument to "write_file" is the filename.

    The next argument(s) is either a hash reference or a flattened hash, "key => value" pairs. The
    following options are available:

    *   append

        The "append" option is a boolean option, defaulted to false (0). Setting this option to true
        (1) will cause the data to be be written at the end of the current file. Internally this
        sets the "sysopen" mode flag "O_APPEND".

        The "append_file" in File::Slurp function sets this option by default.

    *   atomic

        The "atomic" option is a boolean option, defaulted to false (0). Setting this option to true
        (1) will cause the file to be be written to in an atomic fashion. A temporary file name is
        created using "tempfile" in File::Temp. After the file is closed it is renamed to the
        original file name (and "rename" is an atomic operation on most OSes). If the program using
        this were to crash in the middle of this, then the temporary file could be left behind.

    *   binmode

        The "binmode" option is a string option, defaulted to empty (''). If you set the "binmode"
        option, then its value is passed to a call to "binmode" on the opened handle. You can use
        this to set the file to be read in binary mode, utf8, etc. See "perldoc -f binmode" for
        more.

    *   buf_ref

        The "buf_ref" option is used to pass in a scalar reference which has the data to be written.
        If this is set then any data arguments (including the scalar reference shortcut) in @_ will
        be ignored.

    *   err_mode

        The "err_mode" option has three possible values: "quiet", "carp", or the default, "croak".
        In "quiet" mode, all errors will be silent. In "carp" mode, all errors will be emitted as
        warnings. And, in "croak" mode, all errors will be emitted as exceptions. Take a look at
        Try::Tiny or Syntax::Keyword::Try to see how to catch exceptions.

    *   no_clobber

        The "no_clobber" option is a boolean option, defaulted to false (0). Setting this option to
        true (1) will ensure an that existing file will not be overwritten.

    *   perms

        The "perms" option sets the permissions of newly-created files. This value is modified by
        your process's "umask" and defaults to 0666 (same as "sysopen").

        NOTE: this option is new as of File::Slurp version 9999.14.

EXPORT
    These are exported by default or with

            use File::Slurp qw(:std);
            # read_file write_file overwrite_file append_file read_dir

    These are exported with

            use File::Slurp qw(:edit);
            # edit_file edit_file_lines

    You can get all subs in the module exported with

            use File::Slurp qw(:all);

SEE ALSO
    *   File::Slurper - Provides a straightforward set of functions for the most common tasks of
        reading/writing text and binary files.

    *   Path::Tiny - Lightweight and comprehensive file handling, including simple methods for
        reading, writing, and editing text and binary files.

    *   Mojo::File - Similar to Path::Tiny for the Mojo toolkit, always works in bytes.

AUTHOR
    Uri Guttman, <uri AT stemsystems.com>

COPYRIGHT & LICENSE
    Copyright (c) 2003 Uri Guttman. All rights reserved.

    This program is free software; you can redistribute it and/or modify it under the same terms as
    Perl itself.