Is the shell's `source` POSIX-standard?

Question

I've spent some quality time searching the POSIX standard for the shell for the source and . commands, and am at this point convinced that they're just not in there.

Are there any shells that don't support the .? What is the POSIX-standard way of executing a shell script in the current environment (i.e., not spawning a subshell, so if the script says export VAR=value then VAR exists in the calling shell)?

I might be missing something obvious, but it turns out that . is not very easy to Google...

Answer 1

. is standardized (POSIX 2004, 2008).

source is non-standard and specifically not supported in ash, dash or pdksh (so probably it's not in the original Korn Shell either). I.e., it's a Bashism.

Answer 2

It's there under "dot".

NAME

dot - execute commands in the current environment

SYNOPSIS

. file

[etc.]