File and folder Permissions
Permissions are set
using a command called CHMOD. CHMOD stands for CHange MODe. You are giving the
host computer new instructions about this file or directory.
CHMOD comes as a set of 3 numbers. Each of these 3 numbers is a sum total of 3 other numbers. So you have to add 3 numbers to get the first CHMOD number, add 3 numbers to get the second CHMOD number and add 3 numbers to get the third CHMOD number.
Understanding the numbers...
Each digit is a number value from 0 to 7. The value specifies what capabilities are available (or not). These numbers correspond to 3 command types. Read, write and execute.
Read (r) has a value of 4. It allows listing files in the directory.
Write (w) has a value of 2. It allows the addition of new files to the directory.
Execute (x) has a value of 1. It allows access to the files in the directory.
Here are the possible combinations available using these command types :
CHMOD comes as a set of 3 numbers. Each of these 3 numbers is a sum total of 3 other numbers. So you have to add 3 numbers to get the first CHMOD number, add 3 numbers to get the second CHMOD number and add 3 numbers to get the third CHMOD number.
Understanding the numbers...
Each digit is a number value from 0 to 7. The value specifies what capabilities are available (or not). These numbers correspond to 3 command types. Read, write and execute.
Read (r) has a value of 4. It allows listing files in the directory.
Write (w) has a value of 2. It allows the addition of new files to the directory.
Execute (x) has a value of 1. It allows access to the files in the directory.
Here are the possible combinations available using these command types :
Digit
|
rwx
|
Result
|
0
|
---
|
no
access
|
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 execute
|
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