Quick Look At Linux File Permissions
About The Special Permissions Flag
- No special permission set
d Directory
l (small letter L) Symbolic Link
About the rwx
r read permission
w write permission
x execute permission
- no permission
Examples
_rw-rw----
Owner can read/access the file.
Owner can write/change/delete the file.
Owner can not execute file
Group can read/access the file
Group write/change/delete the file.
Group can not execute file
All Users has no permissions
drw-rw-rw
Owner can read/access the directory
Owner can write/change/delete the directory
Group can access the directory
Group write/change/delete the director
All Users can access the directory
All Users can write/change/delete the directory
lkrw-rw-rw
Owner can read/access the file/directory the symbolic link points to
Owner can write/change/delete the file/directory the symbolic link points to
Group can access the file/directory the symbolic link points to
Group write/change/delete the file/directory the symbolic link points to
All Users can access the file/directory the symbolic link points to
All Users can write/change/delete the file/directory the symbolic link points to
I created a symbolic link to helloWorld to demonstrate this.
By entering ls -l helloWORLD at the command prompt the following information was displayed.
As you can see the first flag is the small letter L. Also note the -> points to the path of the actual file hellowWorld the symbolic link file named Link to helloWORLD is linked to.
Other Special Permissions
s - setuid and setgid (short for "set user ID upon execution" and "set group ID upon execution", respectively) The s does not display in the Special Permissions Flag section but instead display in the r of the owner or group section.
t - sticky bit permission. The t does not display in the Special Permissions Flag section but instead display in the x of the owner or group section.
For more in depth study on the Linux/Unix file permissions see:
Understanding Linux File Permissions on Linux.com
Setuid on Wikipedia
Traditional Unix Permissions on Wikipedia