I need to use my $PATH in Emacs to run some commands. How can I make Emacs use it? I installed Emacs from Ubuntu repositories.
$PATH
You can add path settings to /etc/profile.d such as
# /etc/profile.d/path.sh export PATH="$PATH:/usr/local"
In Ubuntu, I remember all sessions source your ~/.xsessionrc, so you also can set path in this file for GUI apps.
~/.xsessionrc