2. Write how to express *nix owner permissions of r-x in binary. (Remember that

Question

2. Write how to express *nix owner permissions of r-x in binary. (Remember that the - symbol means the permission isn’t granted.) What’s the octal representation of the binary number you calculated? (The range of numbers expressed in octal is 0 to 7. Because *nix has three sets of permissions, three sets of 3 binary bits logically represent all possible permissions.)

3. In binary and octal numbering, how do you express granting read, write, and execute permission to the owner of a file and no permissions to anyone else?

4. In binary and octal numbering, how do you express granting read, write, and execute permission to the owner of a file, read and write permission to group, and read permis- sion to other?

Explanation / Answer

2.
Every file has 3 sets of 3 bits

   ---|---|---

The first three bit belog to user/owner
The second three bits for group
The last 3 bits are for others

Now owner is r-x it is 101 (Binary) 5(octal)

3. read, write, execute for the owner, No permissions for anyonel else

   rwx------ = 111000000 - 700

4. read, write, execute for owner - rwx = 111 = 7
   read and write for group = rw- = 110 = 6
   read for other = r-- = 100 = 4

   So the complete set = 764 (octal)
                       = 111110100 (Binary)

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