It looks like /etc/environment is trying to call export, but it is case sensitive.
So I modified /etc/environment from this:
$ cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"
EXPORT GNOME_SHELL_DISABLE_TFP=1
To this:
$ cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"
EXPORT GNOME_SHELL_DISABLE_TFP=1
It looks like /etc/environment is trying to call export, but it is case sensitive.
So I modified /etc/environment from this: usr/local/ sbin:/usr/ local/bin: /usr/sbin: /usr/bin: /sbin:/ bin:/usr/ games" DISABLE_ TFP=1
$ cat /etc/environment
PATH="/
EXPORT GNOME_SHELL_
To this: usr/local/ sbin:/usr/ local/bin: /usr/sbin: /usr/bin: /sbin:/ bin:/usr/ games" DISABLE_ TFP=1
$ cat /etc/environment
PATH="/
EXPORT GNOME_SHELL_
And it works.