OpenWrite

opens a file to write output to it, and returns an OutputStream object.

opens a new file in the default area for temporary files on your computer system.

Details and Options

OpenWrite deletes any existing contents in a file, and prepares to write output starting at the beginning of the file.
The following options can be given:

BinaryFormat	False	whether to use binary format for the file
CharacterEncoding	Automatic	what raw character encoding to use
FormatType	InputForm	default format for printing expressions
NumberMarks	$NumberMarks	when to use ` marks in approximate numbers
PageWidth	78	number of character widths per line
TotalWidth	Infinity	maximum number of character widths for a single expression
Method	Automatic	stream method to use

On computer systems that support pipes, OpenWrite["!command"] runs the external program specified by command, and opens a pipe to send input to it.
If OpenWrite does not succeed in opening a particular file or pipe, it generates a message and returns $Failed.
OpenWrite resolves file names according to the procedure described in "Files and Streams".
OpenWrite returns OutputStream["name",n], where name is the full name of a file or command, and n is a serial number that is unique across all streams opened in the current Wolfram System session.
SetOptions can be used to change the properties of an output stream after it is already open.
Functions like Put and Write automatically open the files or pipes they need, if they are not already open.
With the default setting BinaryFormat->False, the setting for CharacterEncoding is taken to be "ASCII".
OpenWrite[] always creates a new file that does not already exist, in the directory given by $TemporaryDirectory.
With the Method option, the stream is opened using the given input stream method. This overrides the default way that OpenWrite resolves file names.
OpenWrite[File["file"]] is also supported.

Examples

open all close all

Create and open a new stream for writing:

Write an expression to the stream:

Close the stream:

Print the resulting file:

Write an expression to the file specified by the File object: