第四周作业：linux基础

Posted 2020-08-04

本周作业内容：

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。

# ls /home/tuser1 || mkdir /home/tuser1 && cp -R /etc/skel/* /home/tuser1 && chmod -R g-r,o-r /home/tuser1 | ls -l /home/tuser1

-rw-------. 1 root root 0 8月  25 10:59 a.txt 

2、编辑/etc/group文件，添加组hadoop。

 # vim /etc/group 

文件尾部加上一行:    hadoop:x:139:

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。

# vim /etc/passwd

hadoop:x:139:139::/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。

# ls /home/hadoop || mkdir /home/hadoop && cp -R /etc/skel/* /home/hadoop && chmod  g-r,o-r /home/hadoop | ls -ld /home/hadoop

drwx------. 4 hadoop hadoop 4096 8月  25 10:50 /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。

# chown -R hadoop:hadoop /home/hadoop | ls -ld !$ && ls -lA !$

chown -R hadoop:hadoop /home/hadoop | ls -ld /home/hadoop && ls -lA /home/hadoop
drwx------. 4 hadoop hadoop 4096 8月  25 10:50 /home/hadoop
总用量 20
-rw-------. 1 hadoop hadoop    0 8月  25 10:57 a.txt
-rw-------. 1 hadoop hadoop   18 5月  11 05:21 .bash_logout
-rw-------. 1 hadoop hadoop  176 5月  11 05:21 .bash_profile
-rw-------. 1 hadoop hadoop  124 5月  11 05:21 .bashrc
drwx--x--x. 2 hadoop hadoop 4096 11月 12 2010 .gnome2
drwx--x--x. 4 hadoop hadoop 4096 7月  31 22:17 .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；

# grep ^[Ss] /proc/meminfo

SwapCached:            0 kB
SwapTotal:       2031612 kB
SwapFree:        2031612 kB
Shmem:              4028 kB
Slab:              85816 kB
SReclaimable:      19592 kB
SUnreclaim:        66224 kB

# grep -i ^s /proc/meminfo

SwapCached:            0 kB
SwapTotal:       2031612 kB
SwapFree:        2031612 kB
Shmem:              4028 kB
Slab:              85812 kB
SReclaimable:      19588 kB
SUnreclaim:        66224 kB

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

# grep -v "/sbin/nologin" /etc/passwd  | cut -d: -f1,7

root:/bin/bash
sync:/bin/sync
shutdown:/sbin/shutdown
halt:/sbin/halt
admin:/bin/bash
mageia:/bin/bash
slackware:/bin/bash
openstack:/bin/bash
hadoop:/bin/bash
gdm:/bin/bash
abc:/bin/bash
asd:/bin/bash
asdd:/bin/bash
lll:/bin/bash
gentoo:/bin/csh

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

# grep "/bin/bash" /etc/passwd | cut -d: -f1

root
admin
mageia
slackware
openstack
hadoop
gdm
abc
asd
asdd
lll

9、找出/etc/passw d文件中的一位数或两位数；

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

# grep -E "\<[0-9]{1,2}\>" /etc/passwd

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

# grep "^[[:space:]]\+" /boot/grub/grub.conf

              root (hd0,0)
             kernel /vmlinuz-2.6.32-642.el6.x86_64 ro root=/dev/mapper/vg_mycentosl68-lv_root rd_NO_LUKS rd_LVM_LV=vg_mycentosl68/lv_swap crashkernel=auto rd_NO_MD rd_LVM_LV=vg_mycentosl68/lv_root LANG=zh_CN.UTF-8  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；

# grep  "^#[[:space:]]\+[^[:space:]]\+" /etc/rc.d/rc.sysinit

# grep -E "^#[[: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、找出"netstat -tan"命令的结果中以‘LISTEN‘后跟0、1或多个空白字符结尾的行；

# netstat -tan | grep "LISTEN[[:space:]]*$"

tcp        0      0 0.0.0.0:44877             0.0.0.0:*                   LISTEN     
tcp        0      0 0.0.0.0:111                 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     
tcp        0      0 127.0.0.1:6010           0.0.0.0:*                   LISTEN     
tcp        0      0 :::37831                         :::*                        LISTEN     
tcp        0      0 :::111                             :::*                        LISTEN     
tcp        0      0 :::22                               :::*                        LISTEN     
tcp        0      0 ::1:631                           :::*                        LISTEN     
tcp        0      0 ::1:25                             :::*                        LISTEN     
tcp        0      0 ::1:6010                         :::*                        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；

# useradd bash && useradd testbash && useradd basher && useradd -s /sbin/nologin nologin

# 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:3011:3013::/home/bash:/bin/bash
nologin:x:3014:3016::/home/nologin:/sbin/nologin

注：仅供个人作业和学习之用途