chmod

chmod Examples

Let’s change some of the permissions as we discussed a couple of pages ago. Here’s the way our files are now:

-rwxr-xr-x joe acctg archive.sh
-rw-rw-r-- joe acctg orgchart.gif
-rw-rw-r-- joe acctg personnel.txt
-rw-r--r-- joe acctg publicity.html
drwxrwxr-x joe acctg sales
-rw-r----- joe acctg topsecret.inf
-rwxr-xr-x joe acctg wordmatic

First, let’s prevent outsiders from executing archive.sh
Before: -rwxr-xr-x archive.sh
Command: chmod o=r archive.sh
After: -rwxr-xr-- archive.sh

Take away all permissions for the group for topsecret.inf We do this by leaving the permissions part of the command empty.
Before: -rw-r----- topsecret.inf
Command: chmod g= topsecret.inf
After: -rw------- topsecret.inf

Open up publicity.html for reading and writing by anyone.
Before: -rw-r--r-- publicity.html
Command: chmod og=rw publicity.html
After: -rw-rw-rw- publicity.html

source:
http://catcode.com/teachmod/chmod_cmd2.html