This is the official manual for the latest Org-mode release.
:session header argument is for running multiple source code
blocks under one session. Org runs ‘src’ code blocks with the same
session name in the same interpreter process.
noneDefault. Each ‘src’ code block gets a new interpreter process to execute. The process terminates once the block is evaluated.
otherAny string besides
noneturns that string into the name of that session. For example,
:session mysessionnames it ‘mysession’. If
:sessionhas no argument, then the session name is derived from the source language identifier. Subsequent blocks with the same source code language use the same session. Depending on the language, state variables, code from other blocks, and the overall interpreted environment may be shared. Some interpreted languages support concurrent sessions when subsequent source code language blocks change session names.