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

Details and OptionsDetails and Options

  • The following options can be given:
  • BinaryFormatFalsewhether to use binary format for the file
    CharacterEncodingAutomaticwhat raw character encoding to use
    FormatTypeInputFormdefault format for printing expressions
    NumberMarks$NumberMarkswhen to use marks in approximate numbers
    PageWidth78number of character widths per line
    TotalWidthInfinitymaximum number of character widths for a single expression
    MethodAutomaticstream method to use
  • On computer systems that support pipes, OpenAppend["!command"] runs the external program specified by command, and opens a pipe to send input to it.
  • If OpenAppend does not succeed in opening a particular file or pipe, it generates a message, and returns $Failed.
  • OpenAppend resolves file names according to the procedure described in "Files and Streams".
  • OpenAppend 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 .
  • With the Method option, the stream is opened using the given input stream method. This overrides the default way that OpenAppend resolves file names.

ExamplesExamplesopen allclose all

Basic Examples  (1)Basic Examples  (1)

Create a file and write an expression to it:

Click for copyable input
Click for copyable input
Click for copyable input
Click for copyable input

Read the file:

Click for copyable input

Open the file using OpenAppend:

Click for copyable input

Write an expression and close the stream:

Click for copyable input
Click for copyable input

Read the file:

Click for copyable input

Delete the temporary file:

Click for copyable input
Introduced in 1988
| Updated in 2012
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