Re: to enable all profiles at login time

[Wojtek Kosior]

Hi Gottfried,

I see 3 potential problems.

1.
The snippet you addet to .bashrc refers to a variable named
"GUIX_EXTRA_PROFILES". Is this variable defined somewhere? Is seems it
isn't. It should be assigned the path to the directory holding your
profiles so you could for example add a

    GUIX_EXTRA_PROFILES=/path/to/directory/with/my/guix/profiles

line before the `for` loop. Of course, replacing the
"/path/to/directory/with/my/guix/profiles" with the appropriate path
for your system.

2.
Why is `basename` being used here? Consider the following example:

- "GUIX_EXTRA_PROFILES" is set to /home/user/my-extra-guix-stuff
- you have 1 extra Guix profile under
  "/home/user/my-extra-guix-stuff/music"
- the profile mentioned above has its `profile` script under
  "/home/user/my-extra-guix-stuff/music/etc/profile"

Now, let's look at what the

    profile=$i/$(basename "$i")

line does. This line is inside a `for` loop, in each iteration the
variable "i" holds the path to one of the profiles under
"/home/user/my-extra-guix-stuff". In one iteration "i" is going to hold
the string "/home/user/my-extra-guix-stuff/music". The `basename "$i"`
command therefore outputs just "music". So the line we're analyzing
assigns the string "/home/user/my-extra-guix-stuff/music/music" to
variable called "profile". Is this what we wanted? The next line is
going to check for the existence of file
"/home/user/my-extra-guix-stuff/music/music/etc/profile" but it should
instead check for the existence of
"/home/user/my-extra-guix-stuff/music/etc/profile". So you might want
to e.g. replace the line

    profile=$i/$(basename "$i")

with just

    profile=$i

3.
You edited "~/.bash_profile" which is indeed known to be read by bash.

However, this is not that simple. Bash has 3 possible modes of running:
non-interactive shell, interactive shell and (interactive) login shell.
The "login shell" mode is meant to be used when, well, bash is spawned
in a terminal upon user login. "~/.bash_profile" is *only* read by bash
in this mode and not in the other 2. In interactive shell mode, bash
reads "~/.bashrc" *instead*.

When you, for example, execute a `bash` command inside an
already-running shell, the child bash shell that spawns is not going to
consider itself a login shell but rather a mere interactive shell. To
make bash think is is a login shell, you can e.g. start it with a `-l`
flag, like `bash -l`.

The problem is, most terminal emulators by default don't start bash
this way. The 2 solutions I've been using are to either
- change the configuration of one's terminal emulator to start bash
  with `-l`
- or make the ".bashrc" script check if current interactive shell was
  spawned by a teminal emulator process and if yes, have it activate the
  Guix profiles.

The 1st solution is the proper one, the 2nd one is just a workaround
for terminal emulators that are not configurable enough :)


Wojtek


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On Sun, 16 Apr 2023 13:09:00 +0000
Gottfried <gottfried@posteo.de> wrote:

> Hi,
> 
> according to the cookbook
> I added
> --------------------------------------------
> for i in $GUIX_EXTRA_PROFILES/*; do
>    profile=$i/$(basename "$i")
>    if [ -f "$profile"/etc/profile ]; then
>      GUIX_PROFILE="$profile"
>      . "$GUIX_PROFILE"/etc/profile
>    fi
>    unset profile
> done
> -----------------------------------------------
> into my .bash_profile file
> in order to enable all profiles at login time:
> ------------------------------------------------
> My .bash_profile file looks now like that:
> 
> # Honor per-interactive-shell startup file
> if [ -f ~/.bashrc ]; then . ~/.bashrc; fi
> 
> for i in $GUIX_EXTRA_PROFILES/*; do
>    profile=$i/$(basename "$i")
>    if [ -f "$profile"/etc/profile ]; then
>      GUIX_PROFILE="$profile"
>      . "$GUIX_PROFILE"/etc/profile
>    fi
>    unset profile
> done
> -----------------------------------------------
> 
> but when starting MATE Desktop all my profiles are not enabled.
> 
> Could somebody help because probably the two entries in my .bash_profile
> got a mistake.
>

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