w4:权限、grep等练习

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。

[root@centos7 ~]#cp -rv /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@centos7 ~]#chmod -R 700 /home/tuser1/

[root@centos7 ~]#ll -a /home/tuser1/

total 12

drwx------. 3 root root 78 Jul 14 17:19 .

drwxr-xr-x. 11 root root 133 Jul 14 17:19 ..

-rwx------. 1 root root 18 Jul 14 17:19 .bash_logout

-rwx------. 1 root root 193 Jul 14 17:19 .bash_profile

-rwx------. 1 root root 231 Jul 14 17:19 .bashrc

drwx------. 4 root root 39 Jul 14 17:19 .mozilla

2.编辑/etc/group文件，添加组hadoop。

[root@centos7 ~]#vim /etc/group

-使用vim编辑器打开/etc/group文件，输入G跳转到最后一行，然后输入o进入编辑模式，添加：hadoop:x:5004后点击esc键后输入:wq,保存退出。

[root@centos7 ~]#tail -1 /etc/group

hadoop:x:5004

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。

[root@centos7 ~]#vim /etc/passwd

-使用vim编辑器打开/etc/passwd文件，输入G跳转到最后一行，然后输入o进入编辑模式，添加hadoop:x:2003:5004::/home/hadoop:/bin/bash后点击esc键后输入:wq,保存退出：

[root@centos7 ~]#tail -1 /etc/passwd

hadoop:x:2003:5004::/home/hadoop:/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。

[root@centos7 ~]#cp -rv /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@centos7 ~]#chmod 700 /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。

[root@centos7 ~]#chown -R hadoop:hadoop /home/hadoop/

[root@centos7 ~]#ll -a /home/hadoop/

total 12

drwx------. 3 hadoop hadoop 78 Jul 14 20:24 .

drwxr-xr-x. 12 root root 147 Jul 14 20:24 ..

-rw-r--r--. 1 hadoop hadoop 18 Jul 14 20:24 .bash_logout

-rw-r--r--. 1 hadoop hadoop 193 Jul 14 20:24 .bash_profile

-rw-r--r--. 1 hadoop hadoop 231 Jul 14 20:24 .bashrc

drwxr-xr-x. 4 hadoop hadoop 39 Jul 14 20:24 .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；

第一种方式：

[root@centos7 ~]#grep ^[sS] /proc/meminfo 

SwapCached: 0 kB

SwapTotal: 2097148 kB

SwapFree: 2097148 kB

Shmem: 7416 kB

Slab: 75744 kB

SReclaimable: 28976 kB

SUnreclaim: 46768 kB

第二种方式：

[root@centos7 ~]#grep -i ^s /proc/meminfo 

SwapCached: 0 kB

SwapTotal: 2097148 kB

SwapFree: 2097148 kB

Shmem: 7416 kB

Slab: 75744 kB

SReclaimable: 28976 kB

SUnreclaim: 46768 kB

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

[root@centos7 ~]#grep -v "/sbin/nologin$" /etc/passwd

root:x:0:0:root:/root:/bin/bash

sync:x:5:0:sync:/sbin:/bin/sync

shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

halt:x:7:0:halt:/sbin:/sbin/halt

wang:x:1000:1000:wang:/home/wang:/bin/bash

gentoo:x:4001:4001::/home/gentoo:/bin/bash

fedora:x:4002:4002:Fedora Core:/home/fedora:/bin/tcsh

user2:x:4004:4004::/home/user2:/bin/bash

centos:x:4005:4005::/home/centos:/bin/bash

mageia:x:1100:1100::/home/linux:/bin/bash

slackware:x:2002:2016::/home/slackware:/bin/tcsh

hadoop:x:2003:5004::/home/hadoop:/bin/bash

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

[root@centos7 ~]#grep /bin/bash$ /etc/passwd | cut -d: -f1

root

wang

gentoo

user2

centos

mageia

hadoop

9.找出/etc/passwd文件中的一位数或两位数；

方式1：

[root@centos7 ~]#grep "\<[0-9]\{1,2\}\>" /etc/passwd

root:x:0:0:root:/root:/bin/bash

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

sync:x:5:0:sync:/sbin:/bin/sync

shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

halt:x:7:0:halt:/sbin:/sbin/halt

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

nobody:x:99:99:Nobody:/:/sbin/nologin

dbus:x:81:81:System message bus:/:/sbin/nologin

rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin

saslauth:x:996:76:Saslauthd user:/run/saslauthd:/sbin/nologin

rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin

ntp:x:38:38::/etc/ntp:/sbin/nologin

tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin

radvd:x:75:75:radvd user:/:/sbin/nologin

gdm:x:42:42::/var/lib/gdm:/sbin/nologin

sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin

avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin

postfix:x:89:89::/var/spool/postfix:/sbin/nologin

tcpdump:x:72:72::/:/sbin/nologin

方式2：

[root@centos7 ~]#grep "\<[0-9][0-9]\?\>" /etc/passwd 

root:x:0:0:root:/root:/bin/bash

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

sync:x:5:0:sync:/sbin:/bin/sync

shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

halt:x:7:0:halt:/sbin:/sbin/halt

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

nobody:x:99:99:Nobody:/:/sbin/nologin

dbus:x:81:81:System message bus:/:/sbin/nologin

rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin

saslauth:x:996:76:Saslauthd user:/run/saslauthd:/sbin/nologin

rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin

ntp:x:38:38::/etc/ntp:/sbin/nologin

tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin

radvd:x:75:75:radvd user:/:/sbin/nologin

gdm:x:42:42::/var/lib/gdm:/sbin/nologin

sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin

avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin

postfix:x:89:89::/var/spool/postfix:/sbin/nologin

tcpdump:x:72:72::/:/sbin/nologin

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

方式1：

[root@centos6 ~]#grep "^[[:space:]]\+" /boot/grub/grub.conf 

          title CentOS 6 (2.6.32-696.el6.x86_64)

        root (hd0,0)

        kernel /vmlinuz-2.6.32-696.el6.x86_64 ro root=UUID=8b390a6d-81d8-4c7d-a263-1aec5212b535 rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet

        initrd /initramfs-2.6.32-696.el6.x86_64.img

方式2：

[root@centos6 ~]#grep "^[[:space:]]\{1,\}" /boot/grub/grub.conf

          title CentOS 6 (2.6.32-696.el6.x86_64)

        root (hd0,0)

        kernel /vmlinuz-2.6.32-696.el6.x86_64 ro root=UUID=8b390a6d-81d8-4c7d-a263-1aec5212b535 rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet

        initrd /initramfs-2.6.32-696.el6.x86_64.img

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；

[root@centos6 ~]#grep "^#[[:space:]]\{1,\}[^[:space:]]\{1,\}" /etc/rc.d/rc.sysinit    

# /etc/rc.d/rc.sysinit - run once at boot time

# Taken in part from Miquel van Smoorenburg's bcheckrc.

# Check SELinux status

# Print a text banner.

# Only read this once.

# Initialize hardware

# Set default affinity

# Load other user-defined modules

# Load modules (for backward compatibility with VARs)

# Configure kernel parameters

# Set the hostname.

# Sync waiting for storage.

# Device mapper & related initialization

# Start any MD RAID arrays that haven't been started yet

# Remount the root filesystem read-write.

# Clean up SELinux labels

# If relabeling, relabel mount points.

# Mount all other filesystems (except for NFS and /proc, which is already

# mounted). Contrary to standard usage,

# filesystems are NOT unmounted in single user mode.

# The 'no' applies to all listed filesystem types. See mount(8).

# Check to see if a full relabel is needed

# Update quotas if necessary

# Initialize pseudo-random number generator

# Configure machine if necessary.

# Clean out /.

# Do we need (w|u)tmpx files? We don't set them up, but the sysadmin might...

# Clean up /var.

# Clean up utmp/wtmp

# Clean up various /tmp bits

# Make ICE directory

# Start up swapping.

# Set up binfmt_misc

# Boot time profiles. Yes, this should be somewhere else.

# Now that we have all of our basic modules loaded and the kernel going,

# let's dump the syslog ring somewhere so we can find it later

# create the crash indicator flag to warn on crashes, offer fsck with timeout

# Let rhgb know that we're leaving rc.sysinit

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；

[root@centos7 ~]#netstat -tan | grep "LISTEN*[[:space:]]"

tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN     

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 :::111 :::* 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；

[root@centos7 ~]#grep "^\([[:alnum:]]\+\)\>.*\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

或

[root@centos7 ~]#grep -E "^([[:alnum:]]+)\>.*\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