linux系统用户管理与grep正则表达式示例教程

前言

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linux系统用户管理与grep正则表达式

1、复制/etc/skel目录为/home/tuser1，要求/home/tuser1及其内部文件的属组和其它用户均没有任何访问权限。

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[root@suywien ~] # cp -rpv /etc/skel/ /home/tuser1/ ‘ /etc/skel/ ' -> ‘/home/tuser1/' ‘ /etc/skel/ .mozilla ' -> ‘/home/tuser1/.mozilla' ‘ /etc/skel/ .mozilla /extensions ' -> ‘/home/tuser1/.mozilla/extensions' ‘ /etc/skel/ .mozilla /plugins ' -> ‘/home/tuser1/.mozilla/plugins' ‘ /etc/skel/ .bash_logout ' -> ‘/home/tuser1/.bash_logout' ‘ /etc/skel/ .bash_profile ' -> ‘/home/tuser1/.bash_profile' ‘ /etc/skel/ .bashrc ' -> ‘/home/tuser1/.bashrc' [root@suywien ~] # useradd tuser -d /home/tuser1/ useradd : warning: the home directory already exists. Not copying any file from skel directory into it. [root@suywien ~] # chmod -R go-rwx /home/tuser1/ [root@suywien ~] # ll -d /home/tuser1/ drwx------ 3 root root 74 Feb 12 03:04 /home/tuser1/

2、编辑/etc/group文件，添加组hadoop。

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[root@suywien ~] # vim /etc/group [root@suywien ~] # tail -1 /etc/group hadoop:x:1029

3、手动编辑/etc/passwd文件新增一行，添加用户hadoop，其基本组ID为hadoop组的id号；其家目录为/home/hadoop。

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[root@suywien ~] # vim /etc/passwd [root@suywien ~] # tail -1 /etc/passwd hadoop:x:1029:1029:: /home/hodoop/ : /bin/bash

4、复制/etc/skel目录为/home/hadoop，要求修改hadoop目录的属组和其它用户没有任何访问权限。

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[root@suywien ~] # cp -fpv /etc/skel/ /home/hadoop cp : omitting directory ‘ /etc/skel/ ' [root@suywien ~] # cp -fpvR /etc/skel/ /home/hadoop ‘ /etc/skel/ ' -> ‘/home/hadoop' ‘ /etc/skel/ .mozilla ' -> ‘/home/hadoop/.mozilla' ‘ /etc/skel/ .mozilla /extensions ' -> ‘/home/hadoop/.mozilla/extensions' ‘ /etc/skel/ .mozilla /plugins ' -> ‘/home/hadoop/.mozilla/plugins' ‘ /etc/skel/ .bash_logout ' -> ‘/home/hadoop/.bash_logout' ‘ /etc/skel/ .bash_profile ' -> ‘/home/hadoop/.bash_profile' ‘ /etc/skel/ .bashrc ' -> ‘/home/hadoop/.bashrc' [root@suywien ~] # chmod go-rwx /home/hadoop/ [root@suywien ~] # ls -ld /home/hadoop/ drwx------ 3 root root 74 Feb 12 03:04 /home/hadoop/

5、修改/home/hadoop目录及其内部所有文件的属主为hadoop，属组为hadoop。

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[root@suywien ~] # chown -R hadoop:hadoop /home/hadoop/ [root@suywien ~] # ll -al /home/hadoop/ total 16 drwx------ 3 hadoop hadoop 74 Feb 12 03:04 . drwxr-xr-x. 10 root root 4096 Mar 25 10:14 .. -rw-r--r-- 1 hadoop hadoop 18 Nov 20 2015 .bash_logout -rw-r--r-- 1 hadoop hadoop 193 Nov 20 2015 .bash_profile -rw-r--r-- 1 hadoop hadoop 231 Nov 20 2015 .bashrc drwxr-xr-x 4 hadoop hadoop 37 Feb 12 03:03 .mozilla

6、显示/proc/meminfo文件中以大写或小写S开头的行；用两种方式；

1、

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[root@suywien ~] # grep ^[S,s] /proc/meminfo   SwapCached:   0 kB   SwapTotal:  2097148 kB   SwapFree:  2097148 kB   Shmem:    9100 kB   Slab:    89476 kB   SReclaimable:  53176 kB   SUnreclaim:  36300 kB

2、

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[root@suywien ~] # grep -i "^s" /proc/meminfo   SwapCached:   0 kB   SwapTotal:  2097148 kB   SwapFree:  2097148 kB   Shmem:    9100 kB

7、显示/etc/passwd文件中其默认shell为非/sbin/nologin的用户；

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[root@suywien ~] # grep \/sbin\/nologin$ /etc/passwd bin:x:1:1:bin: /bin : /sbin/nologin daemon:x:2:2:daemon: /sbin : /sbin/nologin adm:x:3:4:adm: /var/adm : /sbin/nologin lp:x:4:7:lp: /var/spool/lpd : /sbin/nologin mail:x:8:12:mail: /var/spool/mail : /sbin/nologin ......

8、显示/etc/passwd文件中其默认shell为/bin/bash的用户；

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[root@suywien ~] # grep \/bin\/bash /etc/passwd root:x:0:0:root: /root : /bin/bash roo:x:1000:1000:root: /home/roo : /bin/bash gentoo:x:4001:4001:: /home/gentoo : /bin/bash mageia:x:1100:1100:: /home/linux : /bin/bash tuser:x:4003:4003:: /home/tuser1/ : /bin/bash hadoop:x:1029:1029:: /home/hodoop/ : /bin/bash

9、找出/etc/passwd文件中的一位数或两位数；

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[root@suywien ~] # grep "\<[0-9]\{2,3\}\>" /etc/passwd mail:x:8:12:mail: /var/spool/mail : /sbin/nologin operator:x:11:0:operator: /root : /sbin/nologin games:x:12:100:games: /usr/games : /sbin/nologin ftp :x:14:50:FTP User: /var/ftp : /sbin/nologin ......

10、显示/boot/grub/grub.conf中以至少一个空白字符开头的行；

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[root@suywien ~] # grep "^[[:space:]]\+" /boot/grub2/grub.cfg   load_env   set default= "${next_entry}"   set next_entry=   save_env next_entry   set boot_once= true   ......

11、显示/etc/rc.d/rc.sysinit文件中以#开头，后面跟至少一个空白字符，而后又有至少一个非空白字符的行；

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[root@suywien ~] # grep "^#[[:space:]]\+[^[:space:]]\+" /etc/rc.d/rc.local # THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES # It is highly advisable to create own systemd services or udev rules # to run scripts during boot instead of using this file. # In contrast to previous versions due to parallel execution during boot # this script will NOT be run after all other services. # Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure # that this script will be executed during boot.

12、打出netstat -tan命令执行结果中以‘LISTEN'，后或跟空白字符结尾的行；

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[root@suywien ~] # netstat -tan | grep "LISTEN[[:space:]]*$" tcp  0  0 192.168.122.1:53  0.0.0.0:*    LISTEN  tcp  0  0 0.0.0.0:22    0.0.0.0:*    LISTEN  tcp  0  0 127.0.0.1:631   0.0.0.0:*    LISTEN  tcp  0  0 127.0.0.1:25   0.0.0.0:*    LISTEN  tcp6  0  0 :::22     :::*     LISTEN  tcp6  0  0 ::1:631     :::*     LISTEN  tcp6  0  0 ::1:25     :::*     LISTEN

13、添加用户bash, testbash, basher, nologin (此一个用户的shell为/sbin/nologin)，而后找出当前系统上其用户名和默认shell相同的用户的信息；

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[root@suywien ~] # useradd bash [root@suywien ~] # useradd basher [root@suywien ~] # useradd -s /sbin/nologin nologin   [root@suywien ~] # grep -E "^([^:]+\>).*\1$" /etc/passwd sync :x:5:0: sync : /sbin : /bin/sync shutdown :x:6:0: shutdown : /sbin : /sbin/shutdown halt:x:7:0:halt: /sbin : /sbin/halt bash :x:4004:4004:: /home/bash : /bin/bash nologin:x:4006:4006:: /home/nologin : /sbin/nologin

总结

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原文链接：http://www.178linux.com/92876