BZIP2 (.bz2)

  • Import and Export support the BZIP2 format Version 1.0.
  • Background

      MIME type: application/x-bzip2
      BZIP2 compression method and file format.
      General-purpose lossless compression method.
      Occasionally used for archiving data on Unix systems and for exchanging files on the internet.
      Binary format.
      Compresses data using a combination of the BurrowsWheeler transform and Huffman entropy coding.
      Stores a single file.
      Typically used in combination with TAR.
      Developed and maintained by Julian Seward.
      Introduced in 1996, released as Version 1.0 in 2000.

    Import and Export

    • Import["file.ext.bz2"] uncompresses and imports a BZIP2 compressed archive.
    • Export["file.ext.bz2",expr] exports any expression expr to a BZIP2 compressed file whose format is implied by the file name extension .ext.
    • Import["file.bz2"] uncompresses file.bz2 and imports file, automatically inferring the format from the file contents.
    • Import["file.bz2","format"] uncompresses a BZIP2 file and imports it as "format".
    • Since the Wolfram Language can automatically recognize all common file compression and archive formats, it is never necessary to specify "BZIP2" as a format in the second argument of Import.
    • Import["file.ext.bz2",elem] imports the specified element from file.ext file.
    • Import["file.ext.bz2",{elem,suba,subb,}] imports a subelement.
    • Import["file.ext.bz2",{{elem1,elem2,}}] imports multiple elements.
    • The import format can be explicitly specified with Import["file.bz2",{"format",elems1,elems2,}].
    • Export["file.ext.bz2",expr,elem] creates a BZIP2 compressed .ext file by treating expr as specifying element elem.
    • Export["file.ext.bz2",{expr1,expr2,},{{elem1,elem2,}}] treats each expri as specifying the corresponding elemi.
    • Export["file.ext.bz2",expr,opt1->val1,] exports expr with the specified option elements taken to have the specified values.
    • The export format and BZIP2 compression method can be explicitly specified with Export["file",exprs,{"BZIP2","format",elems}].
    • See the reference pages for full general information on Import and Export.
    • ImportString and ExportString can handle BZIP2 compressed data.


    • The BZIP2 format itself does not support Import or Export elements.
    • Import elements of the BZIP2-compressed file:
    • "Elements" elements and options available in this file
      "Rules"full rules for each element and option
      "Options"rules for options, properties, and settings
    • Import["file.ext.bz2","Elements"] returns the names of elements available in file.ext, effectively unpacking the compressed archive before importing the enclosed file.


    Basic Examples  (2)

    Export a string to a BZIP2-compressed text file:

    Click for copyable input

    Convert the previous output back to a Wolfram Language string:

    Click for copyable input

    Export graphics to a BZIP2-compressed PNG file:

    Click for copyable input

    This gives the available Import elements of the PNG file:

    Click for copyable input

    When importing any element from a BZIP2 file, the Wolfram Language automatically uncompresses it:

    Click for copyable input

    See Also

    "Directory"  "GZIP"  "TAR"  "ZIP"

    Introduced in 2007