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@localhost ~]# cp -r /etc/skel /home/tuser1
[root@localhost ~]# chmod -R 700 /home/tuser1
[root@localhost ~]# ls -ld /home/tuser1
drwx------. 4 root root 4096 Aug 27 15:57 /home/tuser1
2 编辑/etc/group文件，添加组hadoop。
[root@localhost ~]# echo "hadoop:x:1003:" >>/etc/group
[root@localhost ~]# tail -n1 /etc/group
hadoop:x:1003:
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@localhost ~]# echo "hadoop:x:1003:1003:hadoop:/home/hadoop:/bin/bash" >>/etc/passwd
[root@localhost ~]# tail -n1 /etc/passwd
hadoop:x:1003:1003:hadoop:/home/hadoop:/bin/bash
[root@localhost ~]# id hadoop
uid=1003(hadoop) gid=1003(hadoop) groups=1003(hadoop)
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@localhost ~]# cp -r /etc/skel /home/hadoop
[root@localhost ~]# chmod 700 /home/hadoop
[root@localhost ~]# ls -ld /home/hadoop
drwx------. 4 root root 4096 Aug 27 16:22 /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@localhost ~]# chown -R hadoop.hadoop /home/hadoop
[root@localhost ~]# ls -la /home/hadoop
total 28
drwx------. 4 hadoop hadoop 4096 Aug 27 16:22 .
drwxr-xr-x. 13 root root 4096 Aug 27 16:22 ..
-rw-r--r--. 1 hadoop hadoop 18 Aug 27 16:22 .bash_logout
-rw-r--r--. 1 hadoop hadoop 176 Aug 27 16:22 .bash_profile
-rw-r--r--. 1 hadoop hadoop 124 Aug 27 16:22 .bashrc
drwxr-xr-x. 2 hadoop hadoop 4096 Aug 27 16:22 .gnome2
drwxr-xr-x. 4 hadoop hadoop 4096 Aug 27 16:22 .mozilla
[root@localhost ~]# chown -R hadoop:hadoop /home/hadoop
[root@localhost ~]# ls -la /home/hadoop
total 28
drwx------. 4 hadoop hadoop 4096 Aug 27 16:22 .
drwxr-xr-x. 13 root root 4096 Aug 27 16:22 ..
-rw-r--r--. 1 hadoop hadoop 18 Aug 27 16:22 .bash_logout
-rw-r--r--. 1 hadoop hadoop 176 Aug 27 16:22 .bash_profile
-rw-r--r--. 1 hadoop hadoop 124 Aug 27 16:22 .bashrc
drwxr-xr-x. 2 hadoop hadoop 4096 Aug 27 16:22 .gnome2
drwxr-xr-x. 4 hadoop hadoop 4096 Aug 27 16:22 .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；
[root@localhost ~]# grep -i '^s' /proc/meminfo
SwapCached: 0 kB
SwapTotal: 2031612 kB
SwapFree: 2031612 kB
Shmem: 4004 kB
Slab: 86896 kB
SReclaimable: 20608 kB
SUnreclaim: 66288 kB
[root@localhost ~]# grep -i '^[Ss]' /proc/meminfo
SwapCached: 0 kB
SwapTotal: 2031612 kB
SwapFree: 2031612 kB
Shmem: 4004 kB
Slab: 86932 kB
SReclaimable: 20616 kB
SUnreclaim: 66316 kB
7 显示/etc/passwd文件中其默认shell为非/sbin/nologin的用户；
[root@localhost ~]# grep -v '.sbin/nologin' /etc/passwd |cut -d: -f1
root
sync
shutdown
halt
dingpengchao
user7
mageia
slackware
openstack
madriva
hadoop
8 显示/etc/passwd文件中其默认shell为/bin/bash的用户；
[root@localhost ~]# grep 'bin/bash' /etc/passwd |cut -d: -f1
root
dingpengchao
user7
mageia
openstack
madriva
hadoop
9 找出/etc/passwd文件中的一位数或两位数；
[root@localhost ~]# grep -o '\b[0-9]\{1,2\}\b' /etc/passwd
0
0
1
1
2
2
3
4
4
7
5
0
6
0
7
0
8
12
10
14
11
0
12
13
30
14
50
99
99
81
81
69
69
68
68
38
38
48
48
76
89
89
42
42
74
74
72
72
10 显示/boot/grub/grub.conf中以至少一个空白字符开头的行；
[root@localhost ~]# egrep '^[[:space:]]+' /boot/grub/grub.conf
root (hd0,0)
kernel /vmlinuz-2.6.32-642.el6.x86_64 ro root=UUID=98504afb-f211-4129-9a07-675cffc866b0 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-2.6.32-642.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；
[root@localhost ~]# 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；
[root@localhost ~]# netstat -tan |egrep '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@localhost ~]# useradd bash && useradd tsetbash && useradd basher && useradd -s /sbin/nologin nologin
[root@localhost ~]# grep '^\([[:alnum:]]\+\b\).*\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:3005:3008::/home/bash:/bin/bash
nologin:x:3008:3011::/home/nologin:/sbin/nologin
[root@localhost ~]# awk -F '[:/]' '$1==$NF{print$0}' /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:3005:3008::/home/bash:/bin/bash
nologin:x:3008:3011::/home/nologin:/sbin/nologin