You can work through the examples in our Command Line Basics Workshop

or

There is an excellent guide for basic linux commands here

Sharing files with Access Control Lists

If you would like a particular user to access some of your files, you can grant access using Linux ACLs. For example, to allow the user ‘myfriend’ to access+write+execute files in the directory ‘toshare’, the commands would be:

cd 
setfacl -Rdm u:myfriend:rwx toshare
setfacl -Rm u:myfriend:rwx toshare

Note that the enclosing directories need to have the execute bit set, example:

chmod o+x /mnt/ceph/myusername

If you and ‘myfriend’ are in the same primary group (check with the id myfriend command ), you may need to set the execute bit for the group too:

chmod g+x /mnt/ceph/myusername

To remove a users access the command would be

setfacl -x u:myfriend toshare

Or to remove all added ACLs (besides the default)

setfacl --remove-all toshare