file permissions

• Each file and directory has a set of permissions
• Use ls -l to see the permissions (and user and group)
• first char is for directory , next three for user, next three group, last three world
• - rwx rwx rwx
• - rwx --- ---
• d rwx r-x r-x
• use chmod to change permissions
• 4 points for read permission
• 2 points for write permission
• 1 point for execute permission
• Frequently used permissions:
• open dir: chmod 755 dir (rwx r-x r-x)
• closed dir: chmod 700 dir (rwx --- ---)
• open file: chmod 644 file (rw- r-- r--)
• closed file: chmod 600 file (rw- --- ---)
• executable file: chmod 755 file (rwx r-x r-x)
• To protect your work: chmod 700 directory_name
• If you would like to share your files with only one or two other people, use acls. You can set up acls easily with: easyfacl.py. For more information try man setfacl or the Swarthmore CS acl help page