OPS145 Lab 4 Newversion: Difference between revisions
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= Binary review = | = Binary review = | ||
Go back and review the binary stuff we looked at [[OPS145 Introduction#Digital electronics|in the course introduction]]. | |||
This lab is about POSIX permissions, and you need to be completely comfortable with binary-to-decimal and decimal-to-binary conversion from 000 to 111 (decimal 0 to 7). | |||
Here's a summary: | |||
{| class="wikitable" | |||
!Binary | |||
!Decimal | |||
|- | |||
|000 | |||
|0+0+0=0 | |||
|- | |||
|00'''1''' | |||
|0+0+'''1'''=1 | |||
|- | |||
|0'''1'''0 | |||
|0+'''2'''+0=2 | |||
|- | |||
|0'''11''' | |||
|0+'''2'''+'''1'''=3 | |||
|- | |||
|'''1'''00 | |||
|'''4'''+0+0=4 | |||
|- | |||
|'''1'''0'''1''' | |||
|'''4'''+0+'''1'''=5 | |||
|- | |||
|'''11'''0 | |||
|'''4'''+'''2'''+0=6 | |||
|- | |||
|'''111''' | |||
|'''4'''+'''2'''+'''1'''=7 | |||
|} | |||
= Also: = | = Also: = | ||
Revision as of 00:36, 1 February 2024
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Binary review
Go back and review the binary stuff we looked at in the course introduction.
This lab is about POSIX permissions, and you need to be completely comfortable with binary-to-decimal and decimal-to-binary conversion from 000 to 111 (decimal 0 to 7).
Here's a summary:
| Binary | Decimal |
|---|---|
| 000 | 0+0+0=0 |
| 001 | 0+0+1=1 |
| 010 | 0+2+0=2 |
| 011 | 0+2+1=3 |
| 100 | 4+0+0=4 |
| 101 | 4+0+1=5 |
| 110 | 4+2+0=6 |
| 111 | 4+2+1=7 |
Also:
- binary review
- read, write, execute permissions
- for files
- for directories
- owner user, owner group, others
- chmod with octal
- quick adduser with id 1145, passwd
- try examples with two users