Wolfram Language & System 11.0 (2016)|Legacy Documentation

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reads the complete contents of a file and returns it as a string.

reads everything from a stream and returns it as a string.

reads everything generated by an external process and returns it as a string.

reads until the terminator term is encountered.

Details and OptionsDetails and Options

  • ReadString[File["file"],] is also supported.
  • ReadString["file",] and ReadString[File["file",] will first open "file" for reading if it is not already open. The file will be left open unless the default terminator, EndOfFile, is used.
  • ReadString is a blocking function that by default will not return until it has read whatever it is specified to read.
  • With the option setting TimeConstraint->t, ReadString waits at most t seconds, then returns whatever it has read by that time.
  • The terminator term can be any of the following:
  • "string"literal string
    pattstring pattern
    EndOfBufferend of the buffer of available content
    EndOfFileend of the source of content (default)
  • ReadString[src] or ReadString[src,EndOfFile] reads until a stream has ended or the external process providing input has terminated.
  • If ReadString reaches the end of the specified source of content without finding the specified terminator, it will generate a message and return what it has read so far.
  • If ReadString is called on a source of content that has already been exhausted, it returns EndOfFile.
  • ReadString[src,EndOfBuffer] does not block and returns whatever is already available in the input buffer.

ExamplesExamplesopen allclose all

Basic Examples  (2)Basic Examples  (2)

Read a complete file into a string:

Click for copyable input
Click for copyable input

Start the system shell process:

Click for copyable input

Write two commands into the system shell process:

Click for copyable input
Click for copyable input

Read the system shell output without blocking:

Click for copyable input
Introduced in 2014
| Updated in 2016