What’s A CHMOD?

Date: 2011.02.24 | Category: Hosting, WebDesign | Tags:

CHMOD is another name for setting the permissions of files on your server.

All UNIX based web servers understand the concept of permissions. these are broken down into three distinct areas.

Permissions for the person who OWNS the file.
Permissions for the group (all users are members of one or more groups).
Permissions for everyone else.

Permissions are listed one of two ways either using numbers such as 755 or, using letters such as rwx-xr-x however they both mean the same thing.

The first number or first group of three letters stands for the permissions of the owner (IE 7 or rwx).
The second number or second group of letters stands for the permissions of the group (IE 5 or xr).
The third number or third group of letters stands for the permissions of everyone else (IE 5 or x).

The way the system works is as follows:

1 = x = you are able to execute (run) this program.
2 = w = you are able to write to this file.
4 = r = you are able to read the contents of this file.

so if you add it up rwx = 7.

So, in the example given above (755 or rwx-xr-x) the owner is allowed to read and write the file AND execute it.
The group is allowed to execute and write to the file.
Everyone else can execute the file.

We hope this gives you a little more insight to how CHMOD’ing or, setting the permissions on your server can affect how files act.

Article written by Lee