id
id (1p) - return user identity
id (1) - print user identity
root id is 0
id -u return 0 then u r root else not.
e.g
[root@vikas 18-feb]# id -u
0
[root@vikas 18-feb]# id
uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel)
[root@vikas 18-feb]# su vikas
[vikas@vikas 18-feb]$ id
uid=500(vikas) gid=500(vikas) groups=500(vikas)
[vikas@vikas 18-feb]$ id -u
500
[vikas@vikas 18-feb]$ su
if [ `id -u` = "0" ] ; then
echo "u r root"
else
echo " u r not root"
fi
List of groups
ReplyDelete[root@vikas 18-feb]# groups
root bin daemon sys adm disk wheel
[root@vikas 18-feb]# who -m
ReplyDeleteroot pts/1 2009-02-20 16:30 (:0.0)
[root@vikas 18-feb]# lid vikas
vikas(gid=500)
[root@vikas 18-feb]# lid
No user name specified, using root.
root(gid=0)
bin(gid=1)
daemon(gid=2)
sys(gid=3)
adm(gid=4)
disk(gid=6)
wheel(gid=10)
[root@vikas 18-feb]# whatis lid
lid (1) - Display user's groups or group's users
[root@vikas 18-feb]#