cd /
touch test.txt
sudo !!
cd -
touch test.txt
chmod u-w test.txt
nano test.txt
man sudo
cat /etc/passwd ## list all users on the machine
Figure 2 Via Via UC Irvine
Notes: Think twice before sudo. The user flags are u for user, g for
group, o for other, a for all. The permission flags are r for read, w
for write, and x for execute. chmod -x test.sh implies chmod a-x text.sh.
Explore: IBM developerWorks: Manage file permissions and ownership
Bonus:
| octal | decimal | ls -l | permission |
|---|---|---|---|
| 000 | 0 (0+0+0) | — | none |
| 001 | 1 (0+0+1) | –x | execute |
| 010 | 2 (0+2+0) | -w- | write |
| 011 | 3 (0+2+1) | -wx | write + execute |
| 100 | 4 (4+0+0) | r– | read |
| 101 | 5 (4+0+1) | r-x | read + execute |
| 110 | 6 (4+2+0) | rw- | read + write |
| 111 | 7 (4+2+1) | rwx | read + write + execute |
Instead of chmod +rwx test.txt (give everyone permissions to everything) you can
use chmod 777 text.txt.