@@ -3714,7 +3714,7 @@ Guix Profiles in Practice
@section Guix Profiles in Practice
Guix provides a very useful feature that may be quite foreign to newcomers:
-@emph{profiles}. They are a way to group package installations together and all users
+@dfn{profiles}. They are a way to group package installations together and all users
on the same system are free to use as many profiles as they want.
Whether you're a developer or not, you may find that multiple profiles bring you
@@ -3722,6 +3722,16 @@ Guix Profiles in Practice
@emph{traditional package managers}, they are very convenient to use once you've
understood how to set them up.
+@quotation Note
+This section is an opinionated guide on the use of multiple profiles.
+It predates @command{guix shell} and its fast profile cache
+(@pxref{Invoking guix shell,,, guix, GNU Guix Reference Manual}).
+
+In many cases, you may find that using @command{guix shell} to set up
+the environment you need, when you need it, is less work that
+maintaining a dedicated profile. Your call!
+@end quotation
+
If you are familiar with Python's @samp{virtualenv}, you can think of a profile as a
kind of universal @samp{virtualenv} that can hold any kind of software whatsoever, not
just Python software. Furthermore, profiles are self-sufficient: they capture
@@ -4034,29 +4044,12 @@ The benefits of manifests
they ``pin'' packages in the store, which prevents them from being
garbage-collected (@pxref{Invoking guix gc,,, guix, GNU Guix Reference Manual})
and ensures that they will still be available at any point in
-the future.
+the future. The @command{guix shell} command also protects
+recently-used profiles from garbage collection; profiles that have not
+been used for a while may be garbage-collected though, along with the
+packages they refer to.
-Let's take an example:
-
-@enumerate
-@item
-We have an environment for hacking on a project for which there isn't a Guix
-package yet. We build the environment using a manifest, and then run @code{guix
- environment -m manifest.scm}. So far so good.
-
-@item
-Many weeks pass and we have run a couple of @code{guix pull} in the mean time.
-Maybe a dependency from our manifest has been updated; or we may have run
-@code{guix gc} and some packages needed by our manifest have been
-garbage-collected.
-
-@item
-Eventually, we set to work on that project again, so we run @code{guix shell
- -m manifest.scm}. But now we have to wait for Guix to build and install
-stuff!
-@end enumerate
-
-Ideally, we could spare the rebuild time. And indeed we can, all we need is to
+To be 100% sure that a given profile will never be collected,
install the manifest to a profile and use @code{GUIX_PROFILE=/the/profile;
. "$GUIX_PROFILE"/etc/profile} as explained above: this guarantees that our
hacking environment will be available at all times.