add easyshell implementation
add easyshell implementation

tavaresdong/courses,tavaresdong/courses-notes,tavaresdong/courses-notes,tavaresdong/courses,tavaresdong/courses,tavaresdong/courses,tavaresdong/courses-notes,tavaresdong/courses-notes,tavaresdong/courses,tavaresdong/courses,tavaresdong/courses,tavaresdong/courses,tavaresdong/courses