DumpSave ["file.mx",symbol]
writes definitions associated with a symbol to a file in internal Wolfram System format.
DumpSave ["file.mx","context`"]
writes out definitions associated with all symbols in the specified context.
DumpSave ["file.mx",{object1,object2,…}]
writes out definitions for several symbols or contexts.
DumpSave ["package`",objects]
chooses the name of the output file based on the computer system used.
DumpSave
DumpSave ["file.mx",symbol]
writes definitions associated with a symbol to a file in internal Wolfram System format.
DumpSave ["file.mx","context`"]
writes out definitions associated with all symbols in the specified context.
DumpSave ["file.mx",{object1,object2,…}]
writes out definitions for several symbols or contexts.
DumpSave ["package`",objects]
chooses the name of the output file based on the computer system used.
Details and Options
- DumpSave writes out definitions in a binary format that is optimized for input by the Wolfram Language.
- Each file has a plain text header identifying its type and contents.
- Files written by DumpSave can be read by Get .
- Files written by DumpSave cannot be exchanged between operating systems that differ in $SystemWordLength .
- DumpSave will not preserve open stream and link objects.
- Files written by DumpSave conventionally have names that end with .mx.
- DumpSave works with local objects.
- DumpSave ["package`",…] writes a file with a name such as package.mx/(value of $SystemID )/package.mx.
- You can use DumpSave ["file","s"] to write out the definition for the value of a symbol s itself.
- You can typically read a dump file when you start the Wolfram System by using the initfile command‐line option.
- DumpSave [File ["file.mx"],…] is also supported.
Examples
open all close allBasic Examples (1)
Define a function:
Create a temporary file:
Save all definitions for f:
Clear definitions for f:
Verify the definitions have been removed:
Restore the definitions for f from the file:
The definitions have been restored:
Scope (3)
Define and use several functions in a context:
Set the current working directory to the temporary directory:
Save the definitions for all the functions in the context:
Clear the definitions for all the functions in the context:
The functions no longer work:
Read the definitions back in:
The functions work again:
Remove all the functions and reset to the original directory:
Define and use several functions in two contexts:
Save the definitions for all the functions in the context:
Clear all the functions in the contexts:
The functions no longer work:
Read the definitions back in:
All the functions in the context "l2`" work again, but only g was saved and restored in the context "l3`":
Remove all the functions from the two contexts:
Save definitions to a file specified as a File object:
Properties & Relations (1)
Local objects can be used with DumpSave to save definitions persistently:
Clear definitions for f:
Restore the definitions for f from the local object:
See Also
BinarySerialize Save LinkWrite Export Put
Function Repository: CompressWithDefinitions Pacletize
Tech Notes
Related Guides
History
Introduced in 1996 (3.0) | Updated in 2014 (10.0) ▪ 2016 (11.0)
Text
Wolfram Research (1996), DumpSave, Wolfram Language function, https://reference.wolfram.com/language/ref/DumpSave.html (updated 2016).
CMS
Wolfram Language. 1996. "DumpSave." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2016. https://reference.wolfram.com/language/ref/DumpSave.html.
APA
Wolfram Language. (1996). DumpSave. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/DumpSave.html
BibTeX
@misc{reference.wolfram_2025_dumpsave, author="Wolfram Research", title="{DumpSave}", year="2016", howpublished="\url{https://reference.wolfram.com/language/ref/DumpSave.html}", note=[Accessed: 05-December-2025]}
BibLaTeX
@online{reference.wolfram_2025_dumpsave, organization={Wolfram Research}, title={DumpSave}, year={2016}, url={https://reference.wolfram.com/language/ref/DumpSave.html}, note=[Accessed: 05-December-2025]}