755,777, and 775 - What are the differences?

[iphoneuser2008]

When restoring ones apps,,,,one must set permissions.

whats the difference between 777,775, and 755.

Is one better then the other when setting permissions for apps?

[vxphan]

777 world writeable (rwx)
775 Owner (rwx),group(rwx),other (rx)
755 Owner (rwx), group and other (rx)

[navalynt]

Each of the numbers (left to right) indicates a unique permission. It goes owner/group/others. You have three options for each: read (r), write (w), and execute (x) which are expressed with a decimal equivalent as highlighted below:

(r)=4 (w)=2 (x)=1

Therefore, your numbers mean the following:
7 - Full read, write, and execute permissions (4 + 2 + 1 = 7)
5 - Read and execute only permission (4 + 1 = 5)

It seems complicated but once you get it you realize it makes a lot of sense. In most cases you want the creator of the file to have full permissions so you set that to 7. You would want members of the same group as the creator to have access to the files so you can choose either 7 (if you want them to be able to edit/change the files) or 5 (if you want them to only be able to view/execute the files). For all others users, on an iPhone at least, you wouldn't want them editing files if they are not in the right group so you would set this to 5 if you want read/execute access, 4 for read only, or 0 to have no permissions at all. Hence your 777, 775, and 755 you referenced in your post. 5 as the last digit is fine on your iPhone, 4 or 0 would be a little paranoid.

In most cases, on the iPhone, 775 will work fantastic.

Here's a full table of possible numbers and which permissions they are representing:
1 --x execute
2 -w- write
3 -wx write and execute
4 r-- read
5 r-x read and execute
6 rw- read and write
7 rwx read, write and execute