Lecture 3 update

...tors/.ipynb_checkpoints/lec_03_Operators-checkpoint.ipynb

...s/lec_03_Operators_template_Gurmail_lec1-checkpoint.ipynb

...s/lec_03_Operators_template_Gurmail_lec2-checkpoint.ipynb

f23/Gurmail_Lecture_Notes/03_Operators/Mac_command_line.png

...urmail_Lecture_Notes/03_Operators/Window_command_line.png

...Gurmail_Lecture_Notes/03_Operators/lec_03_Operators.ipynb

...03_Operators/lec_03_Operators_template_Gurmail_lec1.ipynb

...03_Operators/lec_03_Operators_template_Gurmail_lec2.ipynb