This is documentation for Mathematica 6, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.2)
Mathematica Expressions in Files
Mathematica's symbolic architecture immediately defines a serializable representation for any Mathematica data or program—which can then readily be stored in a file.
Get (<<) — get Mathematica expressions from a file (.m or .mx file)
Put (>>), PutAppend (>>>) — put Mathematica expressions into a file
Needs declare a file or context to be needed, and loaded if necessary
FilePrint display the contents of a file
NewPackage (.m) create a package-style notebook
Save save variable and function definitions
DumpSave dump definitions into a binary file (.mx file)
Export  ▪ Splice  ▪ Encode  ▪ ToExpression
InitializationCell cell to be evaluated automatically in a notebook