UNIX for Dummies Questions & Answers

in my unix text, an example of user/group/other permissions is given as follows:

drwxr-xr-x

Why are there 2 letter 'r's given under user permissions?

I understand, btw, that d is for directory, not dr.

I appreciate your help.

For directories, having read permission means you can get directory listing. Having execute permission means you can enter that directory.

The three sets of permissions pertain to user (rwx), group (r-x) and others (r-x) respectively.

In addition.

The - does not mean ending user part, but it means no permission set.

We also cal your permission 755, this is a seven for user permission a 5 for group permission and a 5 for others.

The seven is calculated as following :

r w x
4 2 1

Each permission has it's own standard value. So User permission is seven (4 + 2 + 1). Now you understand that your group permission is 5 :

r - x
4 - 1

Regs David

Thank you. If I understand you, one should read the permissions with no spaces at all. In the example above, the permissions are as follows, right?

user: rwx
group: r-x
other: r-x

Thanks again.

Correct!

Forgotten to mention the first character.

d = directory
- = means normal file (Binary or plain text)
c = character device
b = block-device
f = fifo-file
p = pipe-file

Anyway. Don't get confused in it when you see one of the above mentioned characters.

Regs David