Ruby file eof

It blocks only when no data immediately available. This means that it blocks only when following all conditions hold. When readpartial blocks, it waits data or EOF on the stream. If some data is reached, readpartial returns with the data. When readpartial doesn't blocks, it returns or raises immediately.

If the byte buffer is not empty, it returns the data in the buffer. Otherwise if the stream has some content, it returns the data in the stream. The latter means that readpartial is nonblocking-flag insensitive. This may dynamically change the actual class of this stream. Seeks to a given offset anInteger in the stream according to the value of whence :. If single argument is specified, read string from io is tagged with the encoding specified.

If two arguments are specified, those must be encoding objects or encoding names, and the first one is the external encoding, and the second one is the internal encoding. When sync mode is true, all output is immediately flushed to the underlying operating system and is not buffered by Ruby internally. See also IO fsync. When sync mode is true, all output is immediately flushed to the underlying operating system and is not buffered internally.

Returns the new state. Reads maxlen bytes from ios using a low-level read and returns them as a string. Do not mix with other methods that read from ios or you may get unpredictable results. Seeks to a given offset in the stream according to the value of whence see IO seek for values of whence.

Returns the new offset into the file. Writes the given string to ios using a low-level write. Do not mix with other methods that write to ios or you may get unpredictable results.

Raises SystemCallError on error. Pushes back bytes passed as a parameter onto ios , such that a subsequent buffered read will return it. Only one byte may be pushed back before a subsequent read operation that is, you will be able to read only the last of several bytes that have been pushed back.

Has no effect with unbuffered reads such as IO sysread. Pushes back one character passed as a parameter onto ios , such that a subsequent buffered character read will return it. Only one character may be pushed back before a subsequent read operation that is, you will be able to read only the last of several characters that have been pushed back.

Writes the given strings to ios. Returns the number of bytes written in total. The result may also be smaller than string. The caller should care such errors and partial write. Note that this doesn't guarantee to write all data in string. The length written is reported as result and it should be checked later. Hack your world. Feed your head. Live curious.

Home Core 2. Home Classes Methods. In Files file. Parent Object. Files grammar. The Kernel open method can create an IO or File object for these types of arguments: A plain string represents a filename suitable for the underlying operating system.

A string equal to " -" will create another Ruby instance as a subprocess. IO cooked IO cooked! This method returns the number of bytes copied. Synonym for IO. If no block is given, an enumerator is returned instead. Creates a new file for writing if file does not exist. Creates a new file for reading and writing if file does not exist. The following modes must be used separately, and along with one or more of the modes seen above.

The following keys are supported: :mode Same as mode parameter :flags Specifies file open flags as integer. If the value is nil no conversion occurs. See the document of Kernel. Examples: IO. However, several more complicated situations exist. Not the best way to use IO. Opens the given path, returning the underlying file descriptor as a Integer.

It accepts the following keys: :encoding string or encoding Specifies the encoding of the read string. Public Instance Methods ios click to toggle source. TypeError Either advice was not a Symbol , or one of the other arguments was not an Integer.

This list is not exhaustive; other Errno exceptions are also possible. Sets auto-close flag. Returns true if ios is binmode. If ios is opened by IO. Sets a close-on-exec flag. Same as IO stat , but does not follow the last symbolic link. The pathname may not point to the file corresponding to file. For instance, the pathname becomes void when the file has been moved or deleted. Truncates file to at most integer bytes. The file must be opened for writing.

Home Core 2. Home Classes Methods. In Files dir. Parent IO. Files grammar. File A File is an abstraction of any file object accessible by the program and is closely associated with class IO. Returns the birth time for the named file. Returns true if the named file is a block device. Returns true if the named file is a character device. See also Dir::rmdir.

Returns true if the named file exists and has a zero size. Return true if the named file exists. Deprecated method. Don't use. Returns true if the named file exists and is a regular file. To match hidden files that start with a.

Matches any one character. Examples: File. Returns true if the named files are identical. Returns the string representation of the path File. Returns true if the named file is a pipe. Returns the name of the file referenced by the given link.

The last component of the real pathname can be nonexistent. All components of the pathname must exist when this method is called. Returns true if the named file has the setgid bit set. Returns true if the named file has the setuid bit set. Returns true if the named file is a socket. Returns a File::Stat object for the named file see File::Stat. Returns true if the named file has the sticky bit set. STDIN will not be closed.

Returns true if the current file has been closed; false otherwise. Use ARGF. 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 an Integer 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. For example, the following code prints out each line of each named file prefixed with its line number, displaying the filename once per file:.

Iterates over each byte of each file in ARGV. A byte is returned as an Integer in the range After the last byte of the first file has been returned, the first byte of the second file is returned.

After the last character of the first file has been returned, the first character of the second file is returned. After the last codepoint of the first file has been returned, the first codepoint of the second file is returned. Returns true if the current file in ARGF is at end of file, i. The stream must be opened for reading or an IOError will be raised.

The external encoding is the encoding of the text as stored in a file. Contrast with ARGF. Returns the current file as an IO or File object. Returns an integer representing the numeric file descriptor for the current file.

Raises an ArgumentError if there isn't a current file. Gets the next 8-bit byte Returns nil if called at the end of the stream. 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.

The optional limit argument specifies how many characters of each line to return. By default all characters are returned. It's also important for the OP to understand that it's idiomatic to use the block forms of IO and File methods to avoid the need to close files or check for EOF.

It's just another way that Ruby makes programming more sane. Already done. Without testing this, it seems you should perform a rescue rather than checking. Handle it. Niels B. Performing a rescue for an EOF is not necessarily the best tactic, as it is not exceptional behavior to find an eof at the end of a file. And exceptions should be reserved for exceptional behavior, behavior that probably shouldn't happen, or if it does, it wasn't expected to in the normal flow of things.

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