第六周作业

本周作业内容：
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#；
答：

[root@localhost ~]# cp /etc/rc.d/rc.sysinit /tmp/
[root@localhost ~]# sed -i 's/\(^[[:space:]]\)/#\1/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；
答：

[root@localhost ~]# cp /boot/grub/grub.conf /tmp/
[root@localhost ~]# sed  -i 's/^[[:space:]]\+//g' /tmp/grub.conf
[root@localhost ~]# cat /tmp/grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# 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 6 (2.6.32-642.el6.x86_64)
root (hd0,0)
kernel /vmlinuz-2.6.32-642.el6.x86_64 ro root=/dev/mapper/VolGroup-lv_root rd_NO_LUKS LANG=en_US.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-2.6.32-642.el6.x86_64.img
[root@localhost ~]#

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
答：

[root@localhost ~]# sed -i 's/^#[[:space:]]\+//g' /tmp/rc.sysinit

4、为/tmp/grub.conf文件中前三行的行首加#号；
答：

[root@localhost ~]# sed -i '1,3s/\(^.\)/#\1/g' /tmp/grub.conf
[root@localhost ~]# cat /tmp/grub.conf
## grub.conf generated by anaconda
##
## Note that you do not have to rerun grub after making changes to this file
# 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 6 (2.6.32-642.el6.x86_64)
root (hd0,0)
kernel /vmlinuz-2.6.32-642.el6.x86_64 ro root=/dev/mapper/VolGroup-lv_root rd_NO_LUKS LANG=en_US.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-2.6.32-642.el6.x86_64.img
[root@localhost ~]#

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；
答：

[root@localhost ~]#  sed 's/enabled=0/enabled=1/g;s/gpgcheck=0/gpgcheck=1/g' /etc/yum.repos.d/CentOS-Media.repo
# CentOS-Media.repo
#
#  This repo can be used with mounted DVD media, verify the mount point for
#  CentOS-6.  You can use this repo and yum to install items directly off the
#  DVD ISO that we release.
#
# To use this repo, put in your DVD and use it with the other repos too:
#  yum --enablerepo=c6-media [command]
#
# or for ONLY the media repo, do this:
#
#  yum --disablerepo=\* --enablerepo=c6-media [command]

[c6-media]
name=CentOS-$releasever - Media
baseurl=file:///media/CentOS/
file:///media/cdrom/
file:///media/cdrecorder/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
[root@localhost ~]#

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-201608300202
答：

[root@localhost ~]# mkdir /backup
[root@localhost ~]# crontab -e    添加
*/4 * * * * cp -rf /etc /backup/etc\-$(date +"%Y%m%d%H%M")  保存退出。

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-20160830
答：

[root@localhost ~]# mkdir -p /backup/messages_logs
[root@localhost ~]# crontab -e    添加
* * * * 2,4,6 cp -rf /var/log/messages /backup/messages_logs/messages\-$(date +"%Y%m%d") 保存退出。

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
答：

[root@localhost ~]# mkdir /stats
[root@localhost ~]# crontab -e 添加
1 */2 * * * grep "^[s,S]" /proc/meminfo >> /stats/memory.txt  保存退出。

9、工作日的工作时间内，每两小时执行一次echo "howdy"
答：

[root@localhost ~]# crontab -e 添加
* */2 * * 1-5 echo "howdy"  保存退出。

脚本编程练习
10、创建目录/tmp/testdir-当前日期时间;
答：

#!/bin/bash
date=`date +"%Y%m%d%H%M"`
mkdir /tmp/testdir-$date

11、在此目录创建100个空文件：file1-file100
答：

#!/bin/bash
for i in `seq 100` do
touch /tmp/$date/file$i
done

12、显示/etc/passw d文件中位于第偶数行的用户的用户名；
答：

sed -n "n;p" /etc/passwd

13、创建10用户user10-user19；密码同用户名；
答：

#!/bin/bash
for i in {10..19};do
useradd "user$i"
echo "user$i" |passwd --stdin user$i
done

14、在/tmp/创建10个空文件file10-file19;
答：

#!/bin/bash
for i in {10..19};do
mkdir /tmp/file$i
done

15、把file10的属主和属组改为user10，依次类推。
答：

#!/bin/bash
for i in {10..19};do
chown "user$i" /tmp/file$i
done