re: Drafting a Guix blog post on the FHS container

[Jim Newsome]

Sorry for (presumably) breaking threading; I came across this online and 
don't see a way to set my in-reply-to-email header properly.

Anyways just thought I'd mention that I recently learned about this 
feature, and was able to use it to get a downloaded [Tor Browser Bundle] 
running with:


```
guix shell \
  --container \
  --network \
  --emulate-fhs \
  --preserve='^DISPLAY$'
  --share=/run/user/$(id -u)/gdm \
  openssl@1 \
  libevent \
  pciutils \
  dbus-glib \
  bash \
  libgccjit \
  libcxx \
  gtk+ \
  coreutils \
  grep \
  sed \
  file \
  alsa-lib \
  -- \
  ./start-tor-browser.desktop -v
```

`--preserve='^DISPLAY$'` and `--share=/run/user/$(id -u)/gdm` are to get 
access to the display. I'm not sure the second parameter is universally 
correct; I reverse-engineered it via roughly `ps aux | grep -- -auth`.

The `-v` parameter to the browser script keeps it from trying to 
background itself, which otherwise causes the container and browser to 
terminate.

It'd ultimately be nice to package the Tor Browser Bundle properly for 
guix, but it's nice to be able to use it this way in the meantime.

-Jim

[Tor Browser Bundle]: https://www.torproject.org/download/