马哥教育网络班22期+第六周课程练习

1、复制/etc/rc.d/rc.sysinit文件至/tmp目录，将/tmp/rc.sysinit文件中的以至少一个空白字符开头的行的行首加#；

]# cp -v  /etc/rc.d/rc.sysinit /tmp/
    `/etc/rc.d/rc.sysinit' -> `/tmp/rc.sysinit'
]# sed 's@^[[:space:]]\+@#@g' /tmp/rc.sysinit 

2、复制/boot/grub/grub.conf至/tmp目录中，删除/tmp/grub.conf文件中的行首的空白字符；

]# cp -v /boot/grub/grub.conf /tmp/
]# sed 's/^[[:space:]]\+//g' grub.conf

3、删除/tmp/rc.sysinit文件中的以#开头，且后面跟了至少一个空白字符的行行的#和空白字符

]# sed -n '/^#[[:space:]]\+/p' 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,
...
]# sed  '/^#[[:space:]]\+/d' /tmp/rc.sysinit

4、为/tmp/grub.conf文件中前三行的行首加#号；

]# sed '1,3s@^.*@#@g' /tmp/grub.conf 
#
#
#
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/mapper/VolGroup-lv_root
#          initrd /initrd-[generic-]version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.32-431.el6.x86_64)
    root (hd0,0)
    kernel /vmlinuz-2.6.32-431.el6.x86_64 ro root=/dev/mapper/VolGroup-lv_root rd_NO_LUKS.UTF-8 rd_NO_MD rd_LVM_LV=VolGroup/lv_swap SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup/lv_root  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet
    initrd /initramfs-2.6.32-431.el6.x86_64.img

5、将/etc/yum.repos.d/CentOS-Media.repo文件中所有的enabled=0或gpgcheck=0的最后的0修改为1；

]# sed 's@\([enabled|gpgcheck]\)=0@\1=1@g' /etc/yum.repos.d/centos.repo 

6、每4小时执行一次对/etc目录的备份，备份至/backup目录中，保存的目录名为形如etc-201504020202

]# crontab -l
0 */4 * * *  /bin/cp -a /etc /backup/etc-$(date "+%Y%m%d%H%M") &>/dev/null

7、每周2，4，6备份/var/log/messages文件至/backup/messages_logs/目录中，保存的文件名形如messages-20150402

]# crontab -l
0 0 * * 2,4,6 /bin/cp -a /var/log/messages /backup/messages_logs/messages-$(date "+%Y%m%d)" &>/dev/null

8、每天每两小时取当前系统/proc/meminfo文件中的所有以S开头的信息至/stats/memory.txt文件中

]# crontab -l
0 */2 * * * grep "^S" /proc/meminfo >>/stats/memory.txt

9、工作日的工作时间内，每两小时执行一次echo “howdy”

# crontab -l
0 */2,9-18 * * 1-5 /bin/echo "hwdy"

脚本编程练习

10、创建目录/tmp/testdir-当前日期时间;

]# mkdir /tmp/testdir-$(date "+%F-%H-%M-%S")
]# ls -d /tmp/testdir*
 /tmp/testdir-2016-10-16-07-03-50

11、在此目录创建100个空文件：file1-file100

]# touch file{1..100}
]# ll file* |wc -l
100

12、显示/etc/passwd文件中位于第偶数行的用户的用户名；

~]# sed -n 'n;p' /etc/passwd |awk -F: '{print $1}'

13、创建10用户user10-user19；密码同用户名；

#!/bin/bash
#
for i in {10..19};do
    if useradd user$i &>/dev/null ;then
        echo user$i |passwd --stdin user$i
    else
        echo "user$i is exists"
    fi
done

14、在/tmp/创建10个空文件file10-file19;

]# touch file{10..19}

15、把file10的属主和属组改为user10，依次类推。

]# for i in {10..19};do chown user$i:user$i file$i;done