system PATH
On command
echo $PATH are displayed these paths by default. Each path is separated by colon and specificaly these are stored in etc/paths file.
/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin
add PATH
cd or cd ~ takes you to home directory
sudo nano ~/.profile opens hidden file ".profile" in Terminal editor
type export PATH="/Applications/Blender/blender.app/Contents/MacOS:$PATH"
and save it (Ctrl+x). That's all
Note 1: After XQuartz installation (needed to run Inkscape) you can see on echo $PATH also /opt/X11/bin path that is located in etc/paths.d/40XQuartz file. So, if you close and open a new Shell (Terminal window) you should see these path on echo $PATH command like this
/Applications/Blender/blender.app/Contents/MacOS:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin
Note 2: You can add PATH also by editing ".profile" file from Finder. Let "Show hidden files" with Cmd+Shift+. Go to Macintosh HD > Users > "youraccount" folder and open ".profile" file in TextEdit and copy paste
export PATH="/Applications/Blender/blender.app/Contents/MacOS:$PATH" and save it. If you open a new Shell you can see the path on echo $PATH command.
Note 3: I saw paths are stored in other files like .bash_profile (written like /Applications/Blender/blender.app/Contents/MacOS on separate line), but since I already created alias for blender, it make sence to me store also this PATH in one file. I noticed some apps generated already export PATH="...:$PATH" command to ~/.profile so I just mimic that command for blender and it worked. So I hope it's correct :)