【Linux基础】第四周作业

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。

答：#cp -r /etc/skel /home/tuser1

 #chmod -R 700 /home/tuer1

2、编辑/etc/group文件，添加组hadoop。

答：1.#vim /etc/group

#在最后一行添加hadoop:x:1008:

2.echo “hadoop:x:1008:”>> /etc/group

3.groupadd hadoop

[[email protected] ~]# tail -3 /etc/group

basher:x:1006:

nologin:x:1007:

hadoop:x:1008:

3、手动编辑/etc/passw d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。

答：1.#vim /etc/passwd

   #hadoop:x:1008:1008::/home/hadoop:/bin/bash

 2.useradd hadoop -g hadoop

 3.echo “hadoop:x:1008:1008::/home/hadoop:/bin/bash”>> /etc/passwd

[[email protected] ~]# tail -1  /etc/passwd

hadoop:x:1008:1008::/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。

答：#cp -r /etc/skel /home/hadoop

 #chmod -R 700 /home/hadoop

[[email protected] /]# cp -r /etc/skel /home/hadoop

[[email protected] /]# chmod -R 700 /home/hadoop

[[email protected] /]# ll /home/hadoop/

总用量 0

drwx------. 3 root root 74 8月  28 20:54 skel

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

答：chown -R hadoop.hadoop /home/hadoop

[[email protected] /]# chown -R  hadoop.hadoop /home/hadoop/

[[email protected] /]# ll /home/hadoop

总用量 0

drwx------. 3 hadoop hadoop 74 8月  28 20:54 skel

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

答：1.grep ‘^[sS]’ /proc/meminfo

     2.grep -i ‘^s’/proc/meminfo

     3.sed -n ‘/^[sS]/p’ /proc/meminfo

 4.awk ‘/^[sS]/’ /proc/meminfo

[[email protected] /]# grep ^[sS]p’roc/meminfo

SwapCached:        85460 kB

SwapTotal:       2097148 kB

SwapFree:        1813440 kB

Shmem:             10288 kB

Slab:             100628 kB

SReclaimable:      51180 kB

SUnreclaim:        49448 kB

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

答：1.grep -v ‘/sbin/nologin$’/etc/passwd | cut -d: -f1

    2.awk -F: ‘!/\/sbin/nologin/{print $1}’/etc/passwd

[[email protected] /]# grep -v ‘/sbin/nologin‘ /etc/passwd|cut -d: -f1,7

root:/bin/bash

sync:/bin/sync

shutdown:/sbin/shutdown

halt:/sbin/halt

amandabackup:/bin/bash

mysql:/bin/bash

mysq:/bin/bash

user1:/bin/bash

user2:/bin/bash

bash:/bin/bash

testbash:/bin/bash

basher:/bin/bash

hadoop:/bin/bash

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

答：1.grep  ‘/bin/bash$’/etc/passwd | cut -d: -f1,7

    2.awk -F: ‘/\/bin/bash$/{print $1,$7}’/etc/passwd

[[email protected] /]# awk -F: ‘/\/bin\/bash$/{print $1 , $7}‘ /etc/passwd

root /bin/bash

amandabackup /bin/bash

mysql /bin/bash

mysq /bin/bash

user1 /bin/bash

user2 /bin/bash

bash /bin/bash

testbash /bin/bash

basher /bin/bash

hadoop /bin/bash

9、找出/etc/passwd文件中的一位数或两位数；

答：1.grep ‘\<[0-9]\{1,2\}\>’ /etc/passwd

 2.grep -E ‘\<[0-9]{1,2}\>’ /etc/passwd

 3.egrep ‘\<[[:digit:]]{1,2}\>’/etc/passwd

[[email protected] /]# 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

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

amandabackup:x:33:6:Amanda user:/var/lib/amanda:/bin/bash

saslauth:x:994:76:Saslauthd user:/run/saslauthd:/sbin/nologin

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

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

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

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

gdm:x:42:42::/var/lib/gdm:/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

sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/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；

答：1.cat /boot/grub/grub.conf|grep ‘^[[:space:]]’ 

 2.grep ‘^[[:space:]]’ /boot/grub/grub.conf

[[email protected] ~]# grep ‘^[[:space:]]‘ /boot/grub/grub.conf

root (hd0,0)

kernel /vmlinuz-2.6.32-642.el6.x86_64 ro root=UUID=95f5aeee-4932-4521-8a87-7134ed8ae784 rd_NO_LUKS rd_NO_LVM.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet

initrd /initramfs-2.6.32-642.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；

答：

1.grep ‘^#[[:space:]]\+[^[:space:]]\+’/etc/rc.d/rc.sysinit

2.egrep ‘^#[[:space:]]+[^[:space:]]’ /etc/rc.d/rc.sysinit

[[email protected] ~]# egrep ‘^#[[:space:]]+[^[:space:]]‘ /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；

答：netstat -tan | grep ‘LISTEN[[:space:]]*$’

[[email protected] ~]# netstat -tan|grep --color=auto ‘LISTEN[[:space:]]*$‘

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      

tcp        0      0 :::22                       :::*                        LISTEN      

tcp        0      0 ::1:631                     :::*                        LISTEN      

tcp        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；

答：#useradd bash

   #useradd testbash

    #useradd basher

 #useradd nologin -s /sbin/nologin

 #grep ‘^\([[:alnum:]]\+\>\).*\1$’ /etc/passwd

 #egrep ‘^([[:alnum:]]+\>).*\1$’ /etc/passwd

[[email protected] ~]# tail -5  /etc/passwd

user2:x:1003:1003::/home/user2:/bin/bash

bash:x:1004:1004::/home/bash:/bin/bash

testbash:x:1005:1005::/home/testbash:/bin/bash

basher:x:1006:1006::/home/basher:/bin/bash

nologin:x:1007:1007::/home/nologin:/sbin/nologin

[[email protected] /]# 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

bash:x:1004:1004::/home/bash:/bin/bash

nologin:x:1007:1007::/home/nologin:/sbin/nologin

[[email protected] /]# egrep ‘^([[: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

bash:x:1004:1004::/home/bash:/bin/bash

nologin:x:1007:1007::/home/nologin:/sbin/nologin