EuAndreh 写道：
> I got a bit confused by that. On IRC pkill9 mentioned that "git" 
> is a
> package, but "git:send-email" is an output. But isn't "git" the 
> same as
> "git:out"?

No.  Packages are records (the things created by calling (package 
...), and upon which you can call (package-name ...) etc.).

git:out is the default output of the git package, but git:out or 
git:send-email aren't packages in themselves:

$ guix repl
scheme@(guix-user)> ,use (gnu packages)
scheme@(guix-user)> (specification->package "git")
$1 = #<package git@2.28.0 gnu/packages/version-control.scm:157 
790e385bd6e0>
scheme@(guix-user)> (specification->package+output "git")
$2 = #<package git@2.28.0 gnu/packages/version-control.scm:157 
790e385bd6e0>
$3 = "out"
scheme@(guix-user)> (specification->package+output 
"git:send-email")
$4 = #<package git@2.28.0 gnu/packages/version-control.scm:157 
790e385bd6e0>
$5 = "send-email"

In all three cases, the package record is identical, since there's 
only one ‘git’ package record.  Your selected output is simply 
returned as a string.

Kind regards,

T G-R