### Error setting environment variables by sourcing

I'm a beginner of unix and struggling with problems. One of them is to run the sage in any directory by typing 'sage'. I have failed even I tried this for 4 hours. Please help me.

I'm using OS X 10.9 but I don't want to use 'alias'. As a practice I want to change PATH to make it.

I have tried

- adding /Users/jeong/work/Sage/sage-6.4.1/local/bin to /etc/path
using 'vim /etc/paths' I added it to the path. And I closed terminal. After opening it again and typing 'sage'. I got error messages

Error: You must set the SAGE_ROOT environment variable or run this
script from the SAGE_ROOT or SAGE_ROOT/local/bin/ directory.
Error setting environment variables by sourcing '/usr/local/bin/sage-env';
possibly contact sage-devel (see http://groups.google.com/group/sage-devel).

Even I change the '/Users/jeong/work/Sage/sage-6.4.1/local/bin' to '/Users/jeong/work/Sage/sage-6.4.1', it doesn't work.

- making a symbolic link to /usr/local/bin
command: 'ln -s /Users/jeong/work/Sage/sage-6.4.1/local/bin /usr/local/bin'

error messages :

Error: You must set the SAGE_ROOT environment variable or run this
script from the SAGE_ROOT or SAGE_ROOT/local/bin/ directory.
Error setting environment variables by sourcing '/usr/local/bin/sage-env';
possibly contact sage-devel (see http://groups.google.com/group/sage-devel).

- making .bash_profile or changing .profile in the home directory

don't work.

Please help me