Class: ARGF

Inherits:
Object show all
Includes:
Enumerable
Defined in:
io.c,
io.c

Overview

ARGF is a stream designed for use in scripts that process files given as command-line arguments or passed in via STDIN.

The arguments passed to your script are stored in the ARGV Array, one argument per element. ARGF assumes that any arguments that aren’t filenames have been removed from ARGV. For example:

$ ruby argf.rb --verbose file1 file2

ARGV  #=> ["--verbose", "file1", "file2"]
option = ARGV.shift #=> "--verbose"
ARGV  #=> ["file1", "file2"]

You can now use ARGF to work with a concatenation of each of these named files. For instance, ARGF.read will return the contents of file1 followed by the contents of file2.

After a file in ARGV has been read ARGF removes it from the Array. Thus, after all files have been read ARGV will be empty.

You can manipulate ARGV yourself to control what ARGF operates on. If you remove a file from ARGV, it is ignored by ARGF; if you add files to ARGV, they are treated as if they were named on the command line. For example:

ARGV.replace ["file1"]
ARGF.readlines # Returns the contents of file1 as an Array
ARGV           #=> []
ARGV.replace ["file2", "file3"]
ARGF.read      # Returns the contents of file2 and file3

If ARGV is empty, ARGF acts as if it contained STDIN, i.e. the data piped to your script. For example:

$ echo "glark" | ruby -e 'p ARGF.read'
"glark\n"

Instance Method Summary collapse

Methods included from Enumerable

#all?, #any?, #chunk, #collect, #collect_concat, #count, #cycle, #detect, #drop, #drop_while, #each_cons, #each_entry, #each_slice, #each_with_index, #each_with_object, #entries, #find, #find_all, #find_index, #first, #flat_map, #grep, #group_by, #include?, #inject, #lazy, #map, #max, #max_by, #member?, #min, #min_by, #minmax, #minmax_by, #none?, #one?, #partition, #reduce, #reject, #reverse_each, #select, #slice_before, #sort, #sort_by, #take, #take_while, #to_h, #zip

Constructor Details

#initialize ⇒ Object

:nodoc:



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# File 'io.c', line 7632

static VALUE
argf_initialize(VALUE argf, VALUE argv)
{
    memset(&ARGF, 0, sizeof(ARGF));
    argf_init(&ARGF, argv);

    return argf;
}

Instance Method Details

#argv ⇒ Object

Returns the ARGV array, which contains the arguments passed to your script, one per element.

For example:

$ ruby argf.rb -v glark.txt

ARGF.argv   #=> ["-v", "glark.txt"]



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# File 'io.c', line 11627

static VALUE
argf_argv(VALUE argf)
{
    return ARGF.argv;
}

#binmode ⇒ Object

Puts ARGF into binary mode. Once a stream is in binary mode, it cannot be reset to non-binary mode. This option has the following effects:

  • Newline conversion is disabled.

  • Encoding conversion is disabled.

  • Content is treated as ASCII-8BIT.



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# File 'io.c', line 11423

static VALUE
argf_binmode_m(VALUE argf)
{
    ARGF.binmode = 1;
    next_argv();
    ARGF_FORWARD(0, 0);
    rb_io_ascii8bit_binmode(ARGF.current_file);
    return argf;
}

#binmode? ⇒ Boolean

Returns true if ARGF is being read in binary mode; false otherwise. (To enable binary mode use ARGF.binmode.

For example:

ARGF.binmode?  #=> false
ARGF.binmode
ARGF.binmode?  #=> true

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


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# File 'io.c', line 11446

static VALUE
argf_binmode_p(VALUE argf)
{
    return ARGF.binmode ? Qtrue : Qfalse;
}

#bytes ⇒ Object

This is a deprecated alias for each_byte.



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# File 'io.c', line 11265

static VALUE
argf_bytes(VALUE argf)
{
    rb_warn("ARGF#bytes is deprecated; use #each_byte instead");
    if (!rb_block_given_p())
	return rb_enumeratorize(argf, ID2SYM(rb_intern("each_byte")), 0, 0);
    return argf_each_byte(argf);
}

#chars ⇒ Object

This is a deprecated alias for each_char.



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# File 'io.c', line 11304

static VALUE
argf_chars(VALUE argf)
{
    rb_warn("ARGF#chars is deprecated; use #each_char instead");
    if (!rb_block_given_p())
	return rb_enumeratorize(argf, ID2SYM(rb_intern("each_char")), 0, 0);
    return argf_each_char(argf);
}

#close ⇒ Object

Closes the current file and skips to the next in the stream. Trying to close a file that has already been closed causes an IOError to be raised.

For example:

$ ruby argf.rb foo bar

ARGF.filename  #=> "foo"
ARGF.close
ARGF.filename  #=> "bar"
ARGF.close
ARGF.close     #=> closed stream (IOError)



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# File 'io.c', line 11494

static VALUE
argf_close_m(VALUE argf)
{
    next_argv();
    argf_close(argf);
    if (ARGF.next_p != -1) {
	ARGF.next_p = 1;
    }
    ARGF.lineno = 0;
    return argf;
}

#closed? ⇒ Boolean

Returns true if the current file has been closed; false otherwise. Use ARGF.close to actually close the current file.

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


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# File 'io.c', line 11513

static VALUE
argf_closed(VALUE argf)
{
    next_argv();
    ARGF_FORWARD(0, 0);
    return rb_io_closed(ARGF.current_file);
}

#codepoints ⇒ Object

This is a deprecated alias for each_codepoint.



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# File 'io.c', line 11343

static VALUE
argf_codepoints(VALUE argf)
{
    rb_warn("ARGF#codepoints is deprecated; use #each_codepoint instead");
    if (!rb_block_given_p())
	return rb_enumeratorize(argf, ID2SYM(rb_intern("each_codepoint")), 0, 0);
    return argf_each_codepoint(argf);
}

#each(sep = $/) {|line| ... } ⇒ Object #each(sep = $/, limit) {|line| ... } ⇒ Object #each(...) ⇒ Object

ARGF.each_line(sep=$/) {|line| block } -> ARGF

ARGF.each_line(sep=$/,limit) {|line| block }  -> ARGF
ARGF.each_line(...)                           -> an_enumerator

Returns an enumerator which iterates over each line (separated by sep, which defaults to your platform’s newline character) of each file in ARGV. If a block is supplied, each line in turn will be yielded to the block, otherwise an enumerator is returned. The optional limit argument is a Fixnum specifying the maximum length of each line; longer lines will be split according to this limit.

This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last line of the first file has been returned, the first line of the second file is returned. The ARGF.filename and ARGF.lineno methods can be used to determine the filename and line number, respectively, of the current line.

For example, the following code prints out each line of each named file prefixed with its line number, displaying the filename once per file:

ARGF.lines do |line|
  puts ARGF.filename if ARGF.lineno == 1
  puts "#{ARGF.lineno}: #{line}"
end

Overloads:

  • #each(sep = $/) {|line| ... } ⇒ Object

    Yields:

    • (line)
  • #each(sep = $/, limit) {|line| ... } ⇒ Object

    Yields:

    • (line) 


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# File 'io.c', line 11204

static VALUE
argf_each_line(int argc, VALUE *argv, VALUE argf)
{
    RETURN_ENUMERATOR(argf, argc, argv);
    FOREACH_ARGF() {
	argf_block_call(rb_intern("each_line"), argc, argv, argf);
    }
    return argf;
}

#bytes {|byte| ... } ⇒ Object #bytes ⇒ Object

ARGF.each_byte {|byte| block } -> ARGF

ARGF.each_byte                  -> an_enumerator

Iterates over each byte of each file in ARGV. A byte is returned as a Fixnum in the range 0..255.

This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last byte of the first file has been returned, the first byte of the second file is returned. The ARGF.filename method can be used to determine the filename of the current byte.

If no block is given, an enumerator is returned instead.

For example:

ARGF.bytes.to_a  #=> [35, 32, ... 95, 10]

Overloads:

  • #bytes {|byte| ... } ⇒ Object

    Yields:

    • (byte) 


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# File 'io.c', line 11251

static VALUE
argf_each_byte(VALUE argf)
{
    RETURN_ENUMERATOR(argf, 0, 0);
    FOREACH_ARGF() {
	argf_block_call(rb_intern("each_byte"), 0, 0, argf);
    }
    return argf;
}

#each_char {|char| ... } ⇒ Object #each_char ⇒ Object

Iterates over each character of each file in ARGF.

This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last character of the first file has been returned, the first character of the second file is returned. The ARGF.filename method can be used to determine the name of the file in which the current character appears.

If no block is given, an enumerator is returned instead.

Overloads:

  • #each_char {|char| ... } ⇒ Object

    Yields:

    • (char) 


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# File 'io.c', line 11290

static VALUE
argf_each_char(VALUE argf)
{
    RETURN_ENUMERATOR(argf, 0, 0);
    FOREACH_ARGF() {
	argf_block_call(rb_intern("each_char"), 0, 0, argf);
    }
    return argf;
}

#each_codepoint {|codepoint| ... } ⇒ Object #each_codepoint ⇒ Object

Iterates over each codepoint of each file in ARGF.

This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last codepoint of the first file has been returned, the first codepoint of the second file is returned. The ARGF.filename method can be used to determine the name of the file in which the current codepoint appears.

If no block is given, an enumerator is returned instead.

Overloads:

  • #each_codepoint {|codepoint| ... } ⇒ Object

    Yields:

    • (codepoint) 


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# File 'io.c', line 11329

static VALUE
argf_each_codepoint(VALUE argf)
{
    RETURN_ENUMERATOR(argf, 0, 0);
    FOREACH_ARGF() {
	argf_block_call(rb_intern("each_codepoint"), 0, 0, argf);
    }
    return argf;
}

#each(sep = $/) {|line| ... } ⇒ Object #each(sep = $/, limit) {|line| ... } ⇒ Object #each(...) ⇒ Object

ARGF.each_line(sep=$/) {|line| block } -> ARGF

ARGF.each_line(sep=$/,limit) {|line| block }  -> ARGF
ARGF.each_line(...)                           -> an_enumerator

Returns an enumerator which iterates over each line (separated by sep, which defaults to your platform’s newline character) of each file in ARGV. If a block is supplied, each line in turn will be yielded to the block, otherwise an enumerator is returned. The optional limit argument is a Fixnum specifying the maximum length of each line; longer lines will be split according to this limit.

This method allows you to treat the files supplied on the command line as a single file consisting of the concatenation of each named file. After the last line of the first file has been returned, the first line of the second file is returned. The ARGF.filename and ARGF.lineno methods can be used to determine the filename and line number, respectively, of the current line.

For example, the following code prints out each line of each named file prefixed with its line number, displaying the filename once per file:

ARGF.lines do |line|
  puts ARGF.filename if ARGF.lineno == 1
  puts "#{ARGF.lineno}: #{line}"
end

Overloads:

  • #each(sep = $/) {|line| ... } ⇒ Object

    Yields:

    • (line)
  • #each(sep = $/, limit) {|line| ... } ⇒ Object

    Yields:

    • (line) 


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# File 'io.c', line 11204

static VALUE
argf_each_line(int argc, VALUE *argv, VALUE argf)
{
    RETURN_ENUMERATOR(argf, argc, argv);
    FOREACH_ARGF() {
	argf_block_call(rb_intern("each_line"), argc, argv, argf);
    }
    return argf;
}

#eof? ⇒ Boolean #eof ⇒ Boolean

Returns true if the current file in ARGF is at end of file, i.e. it has no data to read. The stream must be opened for reading or an IOError will be raised.

$ echo "eof" | ruby argf.rb

ARGF.eof?                 #=> false
3.times { ARGF.readchar }
ARGF.eof?                 #=> false
ARGF.readchar             #=> "\n"
ARGF.eof?                 #=> true

Overloads:

  • #eof? ⇒ Boolean

    Returns:

    • (Boolean)
  • #eof ⇒ Boolean

    Returns:

    • (Boolean) 


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# File 'io.c', line 10800

static VALUE
argf_eof(VALUE argf)
{
    next_argv();
    if (RTEST(ARGF.current_file)) {
	if (ARGF.init_p == 0) return Qtrue;
	next_argv();
	ARGF_FORWARD(0, 0);
	if (rb_io_eof(ARGF.current_file)) {
	    return Qtrue;
	}
    }
    return Qfalse;
}

#eof? ⇒ Boolean #eof ⇒ Boolean

Returns true if the current file in ARGF is at end of file, i.e. it has no data to read. The stream must be opened for reading or an IOError will be raised.

$ echo "eof" | ruby argf.rb

ARGF.eof?                 #=> false
3.times { ARGF.readchar }
ARGF.eof?                 #=> false
ARGF.readchar             #=> "\n"
ARGF.eof?                 #=> true

Overloads:

  • #eof? ⇒ Boolean

    Returns:

    • (Boolean)
  • #eof ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


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# File 'io.c', line 10800

static VALUE
argf_eof(VALUE argf)
{
    next_argv();
    if (RTEST(ARGF.current_file)) {
	if (ARGF.init_p == 0) return Qtrue;
	next_argv();
	ARGF_FORWARD(0, 0);
	if (rb_io_eof(ARGF.current_file)) {
	    return Qtrue;
	}
    }
    return Qfalse;
}

#external_encoding ⇒ Encoding

Returns the external encoding for files read from ARGF as an Encoding object. The external encoding is the encoding of the text as stored in a file. Contrast with ARGF.internal_encoding, which is the encoding used to represent this text within Ruby.

To set the external encoding use ARGF.set_encoding.

For example:

ARGF.external_encoding  #=>  #<Encoding:UTF-8>

Returns:



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# File 'io.c', line 10584

static VALUE
argf_external_encoding(VALUE argf)
{
    if (!RTEST(ARGF.current_file)) {
	return rb_enc_from_encoding(rb_default_external_encoding());
    }
    return rb_io_external_encoding(rb_io_check_io(ARGF.current_file));
}

#file ⇒ File object

Returns the current file as an IO or File object. #<IO:<STDIN>> is returned when the current file is STDIN.

For example:

$ echo "foo" > foo
$ echo "bar" > bar

$ ruby argf.rb foo bar

ARGF.file      #=> #<File:foo>
ARGF.read(5)   #=> "foo\nb"
ARGF.file      #=> #<File:bar>

Returns:



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# File 'io.c', line 11405

static VALUE
argf_file(VALUE argf)
{
    next_argv();
    return ARGF.current_file;
}

#filename ⇒ String #path ⇒ String

Returns the current filename. “-” is returned when the current file is STDIN.

For example:

$ echo "foo" > foo
$ echo "bar" > bar
$ echo "glark" > glark

$ ruby argf.rb foo bar glark

ARGF.filename  #=> "foo"
ARGF.read(5)   #=> "foo\nb"
ARGF.filename  #=> "bar"
ARGF.skip
ARGF.filename  #=> "glark"

Overloads:



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# File 'io.c', line 11374

static VALUE
argf_filename(VALUE argf)
{
    next_argv();
    return ARGF.filename;
}

#fileno ⇒ Fixnum #to_i ⇒ Fixnum

Returns an integer representing the numeric file descriptor for the current file. Raises an ArgumentError if there isn’t a current file.

ARGF.fileno    #=> 3

Overloads:



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# File 'io.c', line 10752

static VALUE
argf_fileno(VALUE argf)
{
    if (!next_argv()) {
	rb_raise(rb_eArgError, "no stream");
    }
    ARGF_FORWARD(0, 0);
    return rb_io_fileno(ARGF.current_file);
}

#getbyte ⇒ Fixnum?

Gets the next 8-bit byte (0..255) from ARGF. Returns nil if called at the end of the stream.

For example:

$ echo "foo" > file
$ ruby argf.rb file

ARGF.getbyte #=> 102
ARGF.getbyte #=> 111
ARGF.getbyte #=> 111
ARGF.getbyte #=> 10
ARGF.getbyte #=> nil

Returns:



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# File 'io.c', line 11059

static VALUE
argf_getbyte(VALUE argf)
{
    VALUE ch;

  retry:
    if (!next_argv()) return Qnil;
    if (!RB_TYPE_P(ARGF.current_file, T_FILE)) {
	ch = rb_funcall3(ARGF.current_file, rb_intern("getbyte"), 0, 0);
    }
    else {
	ch = rb_io_getbyte(ARGF.current_file);
    }
    if (NIL_P(ch) && ARGF.next_p != -1) {
	argf_close(argf);
	ARGF.next_p = 1;
	goto retry;
    }

    return ch;
}

#getc ⇒ String?

Reads the next character from ARGF and returns it as a String. Returns nil at the end of the stream.

ARGF treats the files named on the command line as a single file created by concatenating their contents. After returning the last character of the first file, it returns the first character of the second file, and so on.

For example:

$ echo "foo" > file
$ ruby argf.rb file

ARGF.getc  #=> "f"
ARGF.getc  #=> "o"
ARGF.getc  #=> "o"
ARGF.getc  #=> "\n"
ARGF.getc  #=> nil
ARGF.getc  #=> nil

Returns:



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# File 'io.c', line 11019

static VALUE
argf_getc(VALUE argf)
{
    VALUE ch;

  retry:
    if (!next_argv()) return Qnil;
    if (ARGF_GENERIC_INPUT_P()) {
	ch = rb_funcall3(ARGF.current_file, rb_intern("getc"), 0, 0);
    }
    else {
	ch = rb_io_getc(ARGF.current_file);
    }
    if (NIL_P(ch) && ARGF.next_p != -1) {
	argf_close(argf);
	ARGF.next_p = 1;
	goto retry;
    }

    return ch;
}

#gets(sep = $/) ⇒ String? #gets(limit) ⇒ String? #gets(sep, limit) ⇒ String?

Returns the next line from the current file in ARGF.

By default lines are assumed to be separated by $/; to use a different character as a separator, supply it as a String for the sep argument.

The optional limit argument specifies how many characters of each line to return. By default all characters are returned.

Overloads:



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# File 'io.c', line 8002

static VALUE
argf_gets(int argc, VALUE *argv, VALUE argf)
{
    VALUE line;

    line = argf_getline(argc, argv, argf);
    rb_lastline_set(line);

    return line;
}

#initialize_copy ⇒ Object

:nodoc:



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# File 'io.c', line 7642

static VALUE
argf_initialize_copy(VALUE argf, VALUE orig)
{
    if (!OBJ_INIT_COPY(argf, orig)) return argf;
    ARGF = argf_of(orig);
    ARGF.argv = rb_obj_dup(ARGF.argv);
    if (ARGF.inplace) {
	const char *inplace = ARGF.inplace;
	ARGF.inplace = 0;
	ARGF.inplace = ruby_strdup(inplace);
    }
    return argf;
}

#inplace_mode ⇒ String

Returns the file extension appended to the names of modified files under inplace-edit mode. This value can be set using ARGF.inplace_mode= or passing the -i switch to the Ruby binary.

Returns:



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# File 'io.c', line 11541

static VALUE
argf_inplace_mode_get(VALUE argf)
{
    if (!ARGF.inplace) return Qnil;
    return rb_str_new2(ARGF.inplace);
}

#inplace_mode=(ext) ⇒ Object

Sets the filename extension for inplace editing mode to the given String. Each file being edited has this value appended to its filename. The modified file is saved under this new name.

For example:

$ ruby argf.rb file.txt

ARGF.inplace_mode = '.bak'
ARGF.lines do |line|
  print line.sub("foo","bar")
end

Each line of file.txt has the first occurrence of “foo” replaced with “bar”, then the new line is written out to file.txt.bak.



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# File 'io.c', line 11574

static VALUE
argf_inplace_mode_set(VALUE argf, VALUE val)
{
    if (rb_safe_level() >= 1 && OBJ_TAINTED(val))
	rb_insecure_operation();

    if (!RTEST(val)) {
	if (ARGF.inplace) free(ARGF.inplace);
	ARGF.inplace = 0;
    }
    else {
	StringValue(val);
	if (ARGF.inplace) free(ARGF.inplace);
	ARGF.inplace = 0;
	ARGF.inplace = strdup(RSTRING_PTR(val));
    }
    return argf;
}

#internal_encoding ⇒ Encoding

Returns the internal encoding for strings read from ARGF as an Encoding object.

If ARGF.set_encoding has been called with two encoding names, the second is returned. Otherwise, if Encoding.default_external has been set, that value is returned. Failing that, if a default external encoding was specified on the command-line, that value is used. If the encoding is unknown, nil is returned.

Returns:



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# File 'io.c', line 10606

static VALUE
argf_internal_encoding(VALUE argf)
{
    if (!RTEST(ARGF.current_file)) {
	return rb_enc_from_encoding(rb_default_external_encoding());
    }
    return rb_io_internal_encoding(rb_io_check_io(ARGF.current_file));
}

#lineno ⇒ Integer

Returns the current line number of ARGF as a whole. This value can be set manually with ARGF.lineno=.

For example:

ARGF.lineno   #=> 0
ARGF.readline #=> "This is line 1\n"
ARGF.lineno   #=> 1

Returns:



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7698
7699
 
# File 'io.c', line 7695

static VALUE
argf_lineno(VALUE argf)
{
    return INT2FIX(ARGF.lineno);
}

#lineno=(integer) ⇒ Integer

Sets the line number of ARGF as a whole to the given Integer.

ARGF sets the line number automatically as you read data, so normally you will not need to set it explicitly. To access the current line number use ARGF.lineno.

For example:

ARGF.lineno      #=> 0
ARGF.readline    #=> "This is line 1\n"
ARGF.lineno      #=> 1
ARGF.lineno = 0  #=> 0
ARGF.lineno      #=> 0

Returns:



7674
7675
7676
7677
7678
7679
7680
 
# File 'io.c', line 7674

static VALUE
argf_set_lineno(VALUE argf, VALUE val)
{
    ARGF.lineno = NUM2INT(val);
    ARGF.last_lineno = ARGF.lineno;
    return Qnil;
}

#lines ⇒ Object

This is a deprecated alias for each_line.



11218
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11220
11221
11222
11223
11224
11225
 
# File 'io.c', line 11218

static VALUE
argf_lines(int argc, VALUE *argv, VALUE argf)
{
    rb_warn("ARGF#lines is deprecated; use #each_line instead");
    if (!rb_block_given_p())
	return rb_enumeratorize(argf, ID2SYM(rb_intern("each_line")), argc, argv);
    return argf_each_line(argc, argv, argf);
}

#filename ⇒ String #path ⇒ String

Returns the current filename. “-” is returned when the current file is STDIN.

For example:

$ echo "foo" > foo
$ echo "bar" > bar
$ echo "glark" > glark

$ ruby argf.rb foo bar glark

ARGF.filename  #=> "foo"
ARGF.read(5)   #=> "foo\nb"
ARGF.filename  #=> "bar"
ARGF.skip
ARGF.filename  #=> "glark"

Overloads:



11374
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11376
11377
11378
11379
 
# File 'io.c', line 11374

static VALUE
argf_filename(VALUE argf)
{
    next_argv();
    return ARGF.filename;
}

#tell ⇒ Integer #pos ⇒ Integer

Returns the current offset (in bytes) of the current file in ARGF.

ARGF.pos    #=> 0
ARGF.gets   #=> "This is line one\n"
ARGF.pos    #=> 17

Overloads:



10672
10673
10674
10675
10676
10677
10678
10679
10680
 
# File 'io.c', line 10672

static VALUE
argf_tell(VALUE argf)
{
    if (!next_argv()) {
	rb_raise(rb_eArgError, "no stream to tell");
    }
    ARGF_FORWARD(0, 0);
    return rb_io_tell(ARGF.current_file);
}

#pos=(position) ⇒ Integer

Seeks to the position given by position (in bytes) in ARGF.

For example:

ARGF.pos = 17
ARGF.gets   #=> "This is line two\n"

Returns:



10710
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10712
10713
10714
10715
10716
10717
10718
 
# File 'io.c', line 10710

static VALUE
argf_set_pos(VALUE argf, VALUE offset)
{
    if (!next_argv()) {
	rb_raise(rb_eArgError, "no stream to set position");
    }
    ARGF_FORWARD(1, &offset);
    return rb_io_set_pos(ARGF.current_file, offset);
}

#print ⇒ nil #print(obj, ...) ⇒ nil

Writes the given object(s) to ios. The stream must be opened for writing. If the output field separator ($,) is not nil, it will be inserted between each object. If the output record separator ($\) is not nil, it will be appended to the output. If no arguments are given, prints $_. Objects that aren’t strings will be converted by calling their to_s method. With no argument, prints the contents of the variable $_. Returns nil.

$stdout.print("This is ", 100, " percent.\n")

produces:

This is 100 percent.

Overloads:

  • #print ⇒ nil

    Returns:

    • (nil)
  • #print(obj, ...) ⇒ nil

    Returns:

    • (nil) 


6817
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6826
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6828
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6840
 
# File 'io.c', line 6817

VALUE
rb_io_print(int argc, VALUE *argv, VALUE out)
{
    int i;
    VALUE line;

    /* if no argument given, print `$_' */
    if (argc == 0) {
	argc = 1;
	line = rb_lastline_get();
	argv = &line;
    }
    for (i=0; i<argc; i++) {
	if (!NIL_P(rb_output_fs) && i>0) {
	    rb_io_write(out, rb_output_fs);
	}
	rb_io_write(out, argv[i]);
    }
    if (argc > 0 && !NIL_P(rb_output_rs)) {
	rb_io_write(out, rb_output_rs);
    }

    return Qnil;
}

#printf(format_string[, obj, ...]) ⇒ nil

Formats and writes to ios, converting parameters under control of the format string. See Kernel#sprintf for details.

Returns:

  • (nil) 


6758
6759
6760
6761
6762
6763
 
# File 'io.c', line 6758

VALUE
rb_io_printf(int argc, VALUE *argv, VALUE out)
{
    rb_io_write(out, rb_f_sprintf(argc, argv));
    return Qnil;
}

#putc(obj) ⇒ Object

If obj is Numeric, write the character whose code is the least-significant byte of obj, otherwise write the first byte of the string representation of obj to ios. Note: This method is not safe for use with multi-byte characters as it will truncate them.

$stdout.putc "A"
$stdout.putc 65

produces:

AA

Returns:



6890
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6892
6893
6894
6895
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6897
6898
6899
6900
6901
6902
6903
 
# File 'io.c', line 6890

static VALUE
rb_io_putc(VALUE io, VALUE ch)
{
    VALUE str;
    if (RB_TYPE_P(ch, T_STRING)) {
	str = rb_str_substr(ch, 0, 1);
    }
    else {
	char c = NUM2CHR(ch);
	str = rb_str_new(&c, 1);
    }
    rb_io_write(io, str);
    return ch;
}

#puts(obj, ...) ⇒ nil

Writes the given objects to ios as with IO#print. Writes a record separator (typically a newline) after any that do not already end with a newline sequence. If called with an array argument, writes each element on a new line. If called without arguments, outputs a single record separator.

$stdout.puts("this", "is", "a", "test")

produces:

this
is
a
test

Returns:

  • (nil) 


6982
6983
6984
6985
6986
6987
6988
6989
6990
6991
6992
6993
6994
6995
6996
6997
6998
6999
7000
7001
7002
7003
7004
7005
7006
7007
7008
7009
7010
7011
 
# File 'io.c', line 6982

VALUE
rb_io_puts(int argc, VALUE *argv, VALUE out)
{
    int i;
    VALUE line;

    /* if no argument given, print newline. */
    if (argc == 0) {
	rb_io_write(out, rb_default_rs);
	return Qnil;
    }
    for (i=0; i<argc; i++) {
	if (RB_TYPE_P(argv[i], T_STRING)) {
	    line = argv[i];
	    goto string;
	}
	if (rb_exec_recursive(io_puts_ary, argv[i], out)) {
	    continue;
	}
	line = rb_obj_as_string(argv[i]);
      string:
	rb_io_write(out, line);
	if (RSTRING_LEN(line) == 0 ||
            !str_end_with_asciichar(line, '\n')) {
	    rb_io_write(out, rb_default_rs);
	}
    }

    return Qnil;
}

#read([length [, outbuf]]) ⇒ String?

Reads length bytes from ARGF. The files named on the command line are concatenated and treated as a single file by this method, so when called without arguments the contents of this pseudo file are returned in their entirety.

length must be a non-negative integer or nil. If it is a positive integer, read tries to read at most length bytes. It returns nil if an EOF was encountered before anything could be read. Fewer than length bytes may be returned if an EOF is encountered during the read.

If length is omitted or is nil, it reads until EOF. A String is returned even if EOF is encountered before any data is read.

If length is zero, it returns _“”_.

If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.

For example:

$ echo "small" > small.txt
$ echo "large" > large.txt
$ ./glark.rb small.txt large.txt

ARGF.read      #=> "small\nlarge"
ARGF.read(200) #=> "small\nlarge"
ARGF.read(2)   #=> "sm"
ARGF.read(0)   #=> ""

Note that this method behaves like fread() function in C. If you need the behavior like read(2) system call, consider ARGF.readpartial.

Returns:



10854
10855
10856
10857
10858
10859
10860
10861
10862
10863
10864
10865
10866
10867
10868
10869
10870
10871
10872
10873
10874
10875
10876
10877
10878
10879
10880
10881
10882
10883
10884
10885
10886
10887
10888
10889
10890
10891
10892
10893
10894
10895
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10897
 
# File 'io.c', line 10854

static VALUE
argf_read(int argc, VALUE *argv, VALUE argf)
{
    VALUE tmp, str, length;
    long len = 0;

    rb_scan_args(argc, argv, "02", &length, &str);
    if (!NIL_P(length)) {
	len = NUM2LONG(argv[0]);
    }
    if (!NIL_P(str)) {
	StringValue(str);
	rb_str_resize(str,0);
	argv[1] = Qnil;
    }

  retry:
    if (!next_argv()) {
	return str;
    }
    if (ARGF_GENERIC_INPUT_P()) {
	tmp = argf_forward(argc, argv, argf);
    }
    else {
	tmp = io_read(argc, argv, ARGF.current_file);
    }
    if (NIL_P(str)) str = tmp;
    else if (!NIL_P(tmp)) rb_str_append(str, tmp);
    if (NIL_P(tmp) || NIL_P(length)) {
	if (ARGF.next_p != -1) {
	    argf_close(argf);
	    ARGF.next_p = 1;
	    goto retry;
	}
    }
    else if (argc >= 1) {
	if (RSTRING_LEN(str) < len) {
	    len -= RSTRING_LEN(str);
	    argv[0] = INT2NUM(len);
	    goto retry;
	}
    }
    return str;
}

#read_nonblock(maxlen) ⇒ String #read_nonblock(maxlen, outbuf) ⇒ Object

Reads at most maxlen bytes from the ARGF stream in non-blocking mode.

Overloads:



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10953
 
# File 'io.c', line 10949

static VALUE
argf_read_nonblock(int argc, VALUE *argv, VALUE argf)
{
    return argf_getpartial(argc, argv, argf, 1);
}

#readbyte ⇒ Fixnum

Reads the next 8-bit byte from ARGF and returns it as a Fixnum. Raises an EOFError after the last byte of the last file has been read.

For example:

$ echo "foo" > file
$ ruby argf.rb file

ARGF.readbyte  #=> 102
ARGF.readbyte  #=> 111
ARGF.readbyte  #=> 111
ARGF.readbyte  #=> 10
ARGF.readbyte  #=> end of file reached (EOFError)

Returns:



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11150
 
# File 'io.c', line 11139

static VALUE
argf_readbyte(VALUE argf)
{
    VALUE c;

    NEXT_ARGF_FORWARD(0, 0);
    c = argf_getbyte(argf);
    if (NIL_P(c)) {
	rb_eof_error();
    }
    return c;
}

#readchar ⇒ String?

Reads the next character from ARGF and returns it as a String. Raises an EOFError after the last character of the last file has been read.

For example:

$ echo "foo" > file
$ ruby argf.rb file

ARGF.readchar  #=> "f"
ARGF.readchar  #=> "o"
ARGF.readchar  #=> "o"
ARGF.readchar  #=> "\n"
ARGF.readchar  #=> end of file reached (EOFError)

Returns:



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11113
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11119
 
# File 'io.c', line 11099

static VALUE
argf_readchar(VALUE argf)
{
    VALUE ch;

  retry:
    if (!next_argv()) rb_eof_error();
    if (!RB_TYPE_P(ARGF.current_file, T_FILE)) {
	ch = rb_funcall3(ARGF.current_file, rb_intern("getc"), 0, 0);
    }
    else {
	ch = rb_io_getc(ARGF.current_file);
    }
    if (NIL_P(ch) && ARGF.next_p != -1) {
	argf_close(argf);
	ARGF.next_p = 1;
	goto retry;
    }

    return ch;
}

#readline(sep = $/) ⇒ String #readline(limit) ⇒ String #readline(sep, limit) ⇒ String

Returns the next line from the current file in ARGF.

By default lines are assumed to be separated by $/; to use a different character as a separator, supply it as a String for the sep argument.

The optional limit argument specifies how many characters of each line to return. By default all characters are returned.

An EOFError is raised at the end of the file.

Overloads:



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# File 'io.c', line 8077

static VALUE
argf_readline(int argc, VALUE *argv, VALUE argf)
{
    VALUE line;

    if (!next_argv()) rb_eof_error();
    ARGF_FORWARD(argc, argv);
    line = argf_gets(argc, argv, argf);
    if (NIL_P(line)) {
	rb_eof_error();
    }

    return line;
}

#readlines(sep = $/) ⇒ Array #readlines(limit) ⇒ Array #readlines(sep, limit) ⇒ Array

ARGF.to_a(sep=$/) -> array

ARGF.to_a(limit)      -> array
ARGF.to_a(sep, limit) -> array

Reads ARGF‘s current file in its entirety, returning an Array of its lines, one line per element. Lines are assumed to be separated by sep.

lines = ARGF.readlines
lines[0]                #=> "This is line one\n"

Overloads:



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# File 'io.c', line 8129

static VALUE
argf_readlines(int argc, VALUE *argv, VALUE argf)
{
    long lineno = ARGF.lineno;
    VALUE lines, ary;

    ary = rb_ary_new();
    while (next_argv()) {
	if (ARGF_GENERIC_INPUT_P()) {
	    lines = rb_funcall3(ARGF.current_file, rb_intern("readlines"), argc, argv);
	}
	else {
	    lines = rb_io_readlines(argc, argv, ARGF.current_file);
	    argf_close(argf);
	}
	ARGF.next_p = 1;
	rb_ary_concat(ary, lines);
	ARGF.lineno = lineno + RARRAY_LEN(ary);
	ARGF.last_lineno = ARGF.lineno;
    }
    ARGF.init_p = 0;
    return ary;
}

#readpartial(maxlen) ⇒ String #readpartial(maxlen, outbuf) ⇒ Object

Reads at most maxlen bytes from the ARGF stream.

If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.

It raises EOFError on end of ARGF stream. Since ARGF stream is a concatenation of multiple files, internally EOF is occur for each file. ARGF.readpartial returns empty strings for EOFs except the last one and raises EOFError for the last one.

Overloads:



10935
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10939
 
# File 'io.c', line 10935

static VALUE
argf_readpartial(int argc, VALUE *argv, VALUE argf)
{
    return argf_getpartial(argc, argv, argf, 0);
}

#rewind ⇒ 0

Positions the current file to the beginning of input, resetting ARGF.lineno to zero.

ARGF.readline   #=> "This is line one\n"
ARGF.rewind     #=> 0
ARGF.lineno     #=> 0
ARGF.readline   #=> "This is line one\n"

Returns:

  • (0) 


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# File 'io.c', line 10732

static VALUE
argf_rewind(VALUE argf)
{
    if (!next_argv()) {
	rb_raise(rb_eArgError, "no stream to rewind");
    }
    ARGF_FORWARD(0, 0);
    return rb_io_rewind(ARGF.current_file);
}

#seek(amount, whence = IO::SEEK_SET) ⇒ 0

Seeks to offset amount (an Integer) in the ARGF stream according to the value of whence. See IO#seek for further details.

Returns:

  • (0) 


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# File 'io.c', line 10689

static VALUE
argf_seek_m(int argc, VALUE *argv, VALUE argf)
{
    if (!next_argv()) {
	rb_raise(rb_eArgError, "no stream to seek");
    }
    ARGF_FORWARD(argc, argv);
    return rb_io_seek_m(argc, argv, ARGF.current_file);
}

#set_encoding(ext_enc) ⇒ Object #set_encoding("ext_enc:int_enc") ⇒ Object #set_encoding(ext_enc, int_enc) ⇒ Object #set_encoding("ext_enc:int_enc", opt) ⇒ Object #set_encoding(ext_enc, int_enc, opt) ⇒ Object

If single argument is specified, strings read from ARGF are tagged with the encoding specified.

If two encoding names separated by a colon are given, e.g. “ascii:utf-8”, the read string is converted from the first encoding (external encoding) to the second encoding (internal encoding), then tagged with the second encoding.

If two arguments are specified, they must be encoding objects or encoding names. Again, the first specifies the external encoding; the second specifies the internal encoding.

If the external encoding and the internal encoding are specified, the optional Hash argument can be used to adjust the conversion process. The structure of this hash is explained in the String#encode documentation.

For example:

ARGF.set_encoding('ascii')         # Tag the input as US-ASCII text
ARGF.set_encoding(Encoding::UTF_8) # Tag the input as UTF-8 text
ARGF.set_encoding('utf-8','ascii') # Transcode the input from US-ASCII
                                   # to UTF-8.



10646
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10649
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10652
10653
10654
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10658
 
# File 'io.c', line 10646

static VALUE
argf_set_encoding(int argc, VALUE *argv, VALUE argf)
{
    rb_io_t *fptr;

    if (!next_argv()) {
	rb_raise(rb_eArgError, "no stream to set encoding");
    }
    rb_io_set_encoding(argc, argv, ARGF.current_file);
    GetOpenFile(ARGF.current_file, fptr);
    ARGF.encs = fptr->encs;
    return argf;
}

#skip ⇒ Object

Sets the current file to the next file in ARGV. If there aren’t any more files it has no effect.

For example:

$ ruby argf.rb foo bar
ARGF.filename  #=> "foo"
ARGF.skip
ARGF.filename  #=> "bar"



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11474
 
# File 'io.c', line 11466

static VALUE
argf_skip(VALUE argf)
{
    if (ARGF.init_p && ARGF.next_p == 0) {
	argf_close(argf);
	ARGF.next_p = 1;
    }
    return argf;
}

#tell ⇒ Integer #pos ⇒ Integer

Returns the current offset (in bytes) of the current file in ARGF.

ARGF.pos    #=> 0
ARGF.gets   #=> "This is line one\n"
ARGF.pos    #=> 17

Overloads:



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# File 'io.c', line 10672

static VALUE
argf_tell(VALUE argf)
{
    if (!next_argv()) {
	rb_raise(rb_eArgError, "no stream to tell");
    }
    ARGF_FORWARD(0, 0);
    return rb_io_tell(ARGF.current_file);
}

#readlines(sep = $/) ⇒ Array #readlines(limit) ⇒ Array #readlines(sep, limit) ⇒ Array

ARGF.to_a(sep=$/) -> array

ARGF.to_a(limit)      -> array
ARGF.to_a(sep, limit) -> array

Reads ARGF‘s current file in its entirety, returning an Array of its lines, one line per element. Lines are assumed to be separated by sep.

lines = ARGF.readlines
lines[0]                #=> "This is line one\n"

Overloads:



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# File 'io.c', line 8129

static VALUE
argf_readlines(int argc, VALUE *argv, VALUE argf)
{
    long lineno = ARGF.lineno;
    VALUE lines, ary;

    ary = rb_ary_new();
    while (next_argv()) {
	if (ARGF_GENERIC_INPUT_P()) {
	    lines = rb_funcall3(ARGF.current_file, rb_intern("readlines"), argc, argv);
	}
	else {
	    lines = rb_io_readlines(argc, argv, ARGF.current_file);
	    argf_close(argf);
	}
	ARGF.next_p = 1;
	rb_ary_concat(ary, lines);
	ARGF.lineno = lineno + RARRAY_LEN(ary);
	ARGF.last_lineno = ARGF.lineno;
    }
    ARGF.init_p = 0;
    return ary;
}

#fileno ⇒ Fixnum #to_i ⇒ Fixnum

Returns an integer representing the numeric file descriptor for the current file. Raises an ArgumentError if there isn’t a current file.

ARGF.fileno    #=> 3

Overloads:



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# File 'io.c', line 10752

static VALUE
argf_fileno(VALUE argf)
{
    if (!next_argv()) {
	rb_raise(rb_eArgError, "no stream");
    }
    ARGF_FORWARD(0, 0);
    return rb_io_fileno(ARGF.current_file);
}

#to_io ⇒ Object

Returns an IO object representing the current file. This will be a File object unless the current file is a stream such as STDIN.

For example:

ARGF.to_io    #=> #<File:glark.txt>
ARGF.to_io    #=> #<IO:<STDIN>>



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# File 'io.c', line 10774

static VALUE
argf_to_io(VALUE argf)
{
    next_argv();
    ARGF_FORWARD(0, 0);
    return ARGF.current_file;
}

#to_s ⇒ String Also known as: inspect

Returns “ARGF”.

Returns:



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# File 'io.c', line 11527

static VALUE
argf_to_s(VALUE argf)
{
    return rb_str_new2("ARGF");
}

#to_write_io ⇒ IO

Returns IO instance tied to ARGF for writing if inplace mode is enabled.

Returns:



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# File 'io.c', line 11652

static VALUE
argf_write_io(VALUE argf)
{
    if (!RTEST(ARGF.current_file)) {
	rb_raise(rb_eIOError, "not opened for writing");
    }
    return GetWriteIO(ARGF.current_file);
}

#write(string) ⇒ Integer

Writes string if inplace mode.

Returns:



11667
11668
11669
11670
11671
 
# File 'io.c', line 11667

static VALUE
argf_write(VALUE argf, VALUE str)
{
    return rb_io_write(argf_write_io(argf), str);
}