103-permissions.md

Unit 3: Permissions

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.