第四周

第四周

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他用户均没有任何访问权限。

[root@node1 ~]# cp -r /etc/skel/ /home/tuser1
[root@node1 ~]# chmod -R go= /home/tuser1
[root@node1 ~]# ls -la /home/tuser1
total 16
drwx------.  2 root root   59 Jul 26 07:24 .
drwxr-xr-x. 11 root root 4096 Jul 26 07:24 ..
-rw-------.  1 root root   18 Jul 26 07:24 .bash_logout
-rw-------.  1 root root  193 Jul 26 07:24 .bash_profile
-rw-------.  1 root root  231 Jul 26 07:24 .bashrc

2.编辑/etc/group文件，添加组hadoop。

[root@node1 ~]# nano /etc/group 
手动添加hadoop:x:5006: 
[root@node1 ~]# tail -1 /etc/group
hadoop:x:5006:

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@node1 ~]# nano /etc/passwd
[root@node1 ~]# tail -1 /etc/passwd
hadoop:x:5006:5006::/home/hadoop:/bin/bash

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

[root@node1 ~]# cp -r /etc/skel /home/hadoop
[root@node1 ~]# chmod go= /home/hadoop
[root@node1 ~]# ls -ld /home/hadoop/
drwx------. 2 root root 59 Jul 26 07:22 /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@node1 ~]# chown -R hadoop:hadoop /home/hadoop
[root@node1 ~]# ls -la /home/hadoop
total 16
drwx------.  2 hadoop hadoop   59 Jul 26 07:22 .
drwxr-xr-x. 11 root   root   4096 Jul 26 07:24 ..
-rw-r--r--.  1 hadoop hadoop   18 Jul 26 07:22 .bash_logout
-rw-r--r--.  1 hadoop hadoop  193 Jul 26 07:22 .bash_profile
-rw-r--r--.  1 hadoop hadoop  231 Jul 26 07:22 .bashrc

6.显示/proc/meminfo文件中以大写S或小写s开头的行；用两种方式。
第一种方法：

[root@node1 ~]# cat /proc/meminfo | grep "^[sS].*"
SwapCached:            0 kB
SwapTotal:       2097148 kB
SwapFree:        2097148 kB
Shmem:              6804 kB
Slab:              60744 kB
SReclaimable:      26144 kB
SUnreclaim:        34600 kB

第二种方法:

[root@node1 ~]# cat /proc/meminfo | grep -v "^[^sS].*"  
SwapCached:            0 kB
SwapTotal:       2097148 kB
SwapFree:        2097148 kB
Shmem:              6804 kB
Slab:              60744 kB
SReclaimable:      26144 kB
SUnreclaim:        34600 kB

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

[root@node1 ~]# grep -v "/sbin/nologin" /etc/passwd | cut -d : -f 1
root
sync
shutdown
halt
centos
redhat
fedora
mint
mageia
slackware
hadoop

8.显示/etc/passwd文件中其默认shell为/bin/bash的用户。
第一种方法：

[root@node1 ~]# grep "/bin/bash" /etc/passwd | grep -o "^[^:]\+"
root
centos
redhat
fedora
mint
mageia
hadoop

第二种方法：

[root@node1 ~]# grep "/bin/bash" /etc/passwd | cut -d : -f 1
root
centos
redhat
fedora
mint
mageia
hadoop

9.找出/etc/passwd中的一位数或二位数。

[root@node1 ~]# 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
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin

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

[root@node1 ~]# grep --color=auto "^[[:space:]]\+.*$" /boot/grub/grub.conf 
root (hd0,0)
kernel /vmlinuz-2.6.32-573.el6.x86_64 ro root=UUID=c5e05cf4-7e32-402e-aefa-1353baf6df38 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-2.6.32-573.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，而后又至少一个非空白字符的行。

[root@magedu ~]# grep "^#[[: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).
# Update quotas if necessary
# Check to see if a full relabel is needed
# 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.打印出netstat -tan命令执行结果中以‘LISTEN’，后或跟空白字符结尾的行。

[root@magedu ~]# netstat -tan | grep -o "\<LISTEN[[:space:]]\+.*$"
LISTEN      
LISTEN      
LISTEN      
LISTEN

13.添加用户bash，testbash，basher，nologin(此用户的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。
用grep：

[root@node1 ~]# grep "^\([a-z]\+\)\>.*\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:5007:5007::/home/bash:/bin/bash
nologin:x:5010:5010::/home/nologin:/sbin/nologin

用egrep：

[root@node1 ~]# egrep "^([a-z]+)\>.*\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:5007:5007::/home/bash:/bin/bash
nologin:x:5010:5010::/home/nologin:/sbin/nologin