1、who | cut -d" " -f1 | sort -u

2、lastlog | grep "\<tty"

lastlog | grep -v "[**]"

3、cut -d: -f7 /etc/passwd | sort -f | uniq -c -d | sort -r | head -1 | grep -E -o "/.*"

4、cat /etc/passwd | sort -nrk 3 -t : | head -10 | tr 'a-z' 'A-Z' > /tmp/maxusers.txt

5、ifconfig eth0 | grep -E -o "addr:[0-9.]+" | cut -d: -f2

ifconfig eth0 | grep -E -o "addr:[0-9.]+" | grep -E -o "[0-9.]+"

6、ls /etc/ | grep ".conf"$ | tr 'a-z' 'A-Z' > /tmp/etc.conf

7、ls /var | wc -w

8、cat /etc/group | sort -nk 3 -t : | cut -d: -f1 | head -10

9、cat /etc/fstab /etc/issue > /tmp/etc.test

10、

(1)groupadd -g 2016 distro

(2)useradd -u 1005 -g distro mandriva

(3)useradd -d /home/linux -u 1100 mageia

(4)passwd mandriva

(5)userdel mandriva

(6)useradd -u 2002 -g distro -G peguin slackware

(7)usermod -s /bin/tcsh slackware

(8)usermod -a -G admins slackware

Linux正則及用戶管理練習