is to run the command
sudo ln -s `pwd`/sage /usr/local/bin
After that, from any location, running
sage
will launch Sage.
You can also start other software shipped by Sage. Namely,
sage --gap
sage --gp
sage --ipython
sage --maxima
sage --R
sage --singular
will respectively run the versions of GAP, PARI/GP, IPython,
Maxima, R, Singular, shipped by Sage.
If you then also run this command in the terminal:
sudo sage -c "install_scripts('/usr/local/bin')"
then you will be able to start these other programs directly by:
gap
gp
ipython
maxima
R
Singular
(if these commands already existed in your system, they will
not be overwritten).