处理linux中的组权限

Question

I can't understand how exactly this works in Linux.

For example, I want only users in some group have access to execute some file (I hope this is possible without visudo ).

I create a system user and system group like:

 useradd -K UID_MIN=100 -K UID_MAX=499 -K GID_MIN=100 -K GID_MAX=499 -p \* -s /sbin/nologin -c "testusr daemon,,,"  -d "/var/testusr" testusr

I add my current user user to the group testusr (may be not cross platform):

 adduser user testusr

I create some test shell file and set permissions:

 touch test.sh
 chmod ug+x test.sh
 sudo chown testusr:testusr test.sh

But I still can't start test.sh as user :

 ./test.sh
 -> Error

Now I look for some system groups like cdrom to check how they work. My user is in cdrom group and can use the cd rom on my computer:

$ ls -al /dev/cdrom
lrwxrwxrwx 1 root root 3 апр.  17 12:55 /dev/cdrom -> sr0
$ ls -al /dev/sr0
brw-rw----+ 1 root cdrom 11, 0 апр.  17 12:55 /dev/sr0

Addition:

./test.sh command starts to work as I want after system reboot. Strange...

I'm on Ubuntu Studio 15.10

Answer 1

只有在重新登录时才会反映组更改。