Hello! I was trying to run these commands on my ros folder and i got a error saying permission denied. How can i fix this?

 bash: /home/a/ros/devel/setup.bash: No such file or directory

 bash: /home/a/ros/devel/setup.bash: No such file or directory

 a@a:~/ros$ git pull

 error: cannot open .git/FETCH_HEAD: Permission denied

  a@a:~/ros$ catkin_make

Base path: /home/a/ros

Source space: /home/a/ros/src

Build space: /home/a/ros/build

Devel space: /home/a/ros/devel

Install space: /home/a/ros/install

[Errno 13] Permission denied: '/home/a/ros/build'

Thanks