1、写一个脚本，判断当前系统上所有用户的shell是否为可登录shell（即用户的shell不是/sbin/nologin）；分别这两类用户的个数；通过字符串比较来实现；

[root@localhost ~]# vim usershell.sh
#!/bin/bash
#
declare -i nologin_num=0
declare -i login_num=0
for i in $(cut -d: -f7 /etc/passwd);doif [ "$i" == "/sbin/nologin" ];thenlet nologin_num++elselet login_num++fi
done
echo "The total number of user shell that can't login is :$nologin_num"
echo "The total number of user shell that can login is :$login_num"

脚本测试

[root@localhost ~]# bash usershell.sh
The total number of user shell that can't login is :33
The total number of user shell that can login is :5
[root@localhost ~]# grep -o /sbin/nologin /etc/passwd | wc -l
33
[root@localhost ~]# grep -v /sbin/nologin /etc/passwd | wc -l
5

2、写一个脚本

(1) 获取当前主机的主机名，保存于hostname变量中；

(2) 判断此变量的值是否为localhost，如果是，则将当前主机名修改为www.magedu.com；

(3) 否则，则显示当前主机名；

vim hostnametest.sh
#!/bin/bash
#
hostname=$(hostname)
if [ "$hostname" == "localhost" ];thenhostname www.magedu.comecho "Hostname has changed to www.magedu.com"
elseecho "Current hostname is $hostname"
fi

脚本测试

[root@localhost ~]# hostname
localhost
[root@localhost ~]# bash hostnametest.sh
Hostname has changed to www.magedu.com
[root@localhost ~]# hostname
www.magedu.com
[root@localhost ~]# bash hostnametest.sh
Current hostname is www.magedu.com

3、写一个脚本，完成如下功能

(1) 传递一个磁盘设备文件路径给脚本，判断此设备是否存在；

(2) 如果存在，则显示此设备上的所有分区信息；

vim devicetest.sh
#!/bin/bash
#
read -p "Please input a device path:" devicepath
if [ -z $devicepath ];thenecho "Usage: Please input a device path"exit 1
fi
if [ -b $devicepath ];thenfdisk -l $devicepath
elseecho "No such device"
fi

脚本测试

[root@localhost ~]# bash devicetest.sh
Please input a device path:
Usage: Please input a device path
[root@localhost ~]# bash devicetest.sh
Please input a device path:/dev/sdb
No such device
[root@localhost ~]# bash devicetest.sh
Please input a device path:/dev/sda
Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000a0ae7Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     1026047      512000   83  Linux
/dev/sda2         1026048    41943039    20458496   8e  Linux LVM

4、写一个脚本，完成如下功能

脚本能够接受一个参数；

(1) 如果参数1为quit，则显示退出脚本，并执行正常退出；

(2) 如果参数1为yes，则显示继续执行脚本；

(3) 否则，参数1为其它任意值，均执行非正常退出；

vim parametertest.sh
#!/bin/bash
#
read -p "Please input a word(quit|yes):" parameter
while true;do
case $parameter in
quit)
echo "exit the script"
exit 0
;;
yes)
echo "continue to excute the script"
read -p "Please input a word(quit|yes):" parameter
;;
*)
echo "error exit"
exit 1
;;
esac
done

脚本测试

[root@localhost ~]# bash parametertest.sh
Please input a word(quit|yes):quit
exit the script
[root@localhost ~]# bash parametertest.sh
Please input a word(quit|yes):yes
continue to excute the script
Please input a word(quit|yes):quit
exit the script
[root@localhost ~]# bash parametertest.sh
Please input a word(quit|yes):
error exit
[root@localhost ~]# bash parametertest.sh
Please input a word(quit|yes):yes
continue to excute the script
Please input a word(quit|yes):
error exit

5、写一个脚本，完成如下功能

传递一个参数给脚本，此参数为gzip、bzip2或者xz三者之一；

(1) 如果参数1的值为gzip，则使用tar和gzip归档压缩/etc目录至/backups目录中，并命名为/backups/etc-20160613.tar.gz；

(2) 如果参数1的值为bzip2，则使用tar和bzip2归档压缩/etc目录至/backups目录中，并命名为/backups/etc-20160613.tar.bz2；

(3) 如果参数1的值为xz，则使用tar和xz归档压缩/etc目录至/backups目录中，并命名为/backups/etc-20160613.tar.xz；

(4) 其它任意值，则显示错误压缩工具，并执行非正常退出；

vim compresstest.sh
#!/bin/bash
#
if [ ! -e /backups ];then
mkdir /backups
fi
read -p "Please choose a format of compression(gzip|bzip2|xz):" zip
case $zip in
gzip)
tar -zcf /backups/etc-$(date +%Y%m%d).tar.gz /etc
;;
bzip2)
tar -jcf /backups/etc-$(date +%Y%m%d).tar.bz2 /etc
;;
xz)
tar -Jcf /backups/etc-$(date +%Y%m%d).tar.xz /etc
;;
*)
echo "error compression format"
exit 1
;;
esac

脚本测试

[root@localhost ~]# ls /backups
ls: cannot access /backups: No such file or directory
[root@localhost ~]# bash compresstest.sh
Please choose a format of compression(gzip|bzip2|xz):gzip
[root@localhost ~]# bash compresstest.sh
Please choose a format of compression(gzip|bzip2|xz):bzip2
[root@localhost ~]# bash compresstest.sh
Please choose a format of compression(gzip|bzip2|xz):xz
[root@localhost ~]# bash compresstest.sh
Please choose a format of compression(gzip|bzip2|xz):
error compression format
[root@localhost ~]# ls /backups/
etc-20170624.tar.bz2  etc-20170624.tar.gz  etc-20170624.tar.xz

6、写一个脚本，接受一个路径参数：

(1) 如果为普通文件，则说明其可被正常访问；

(2) 如果是目录文件，则说明可对其使用cd命令；

(3) 如果为符号链接文件，则说明是个访问路径；

(4) 其它为无法判断；

vim pathtest.sh
#!/bin/bash
#
read -p "Please input a path:" path
if [ -f $path ];thenecho "${path} can be visited"cat $path
elif [ -d $path ];thenecho "${path} can use 'cd' command"
elif [ -h $path ];thenecho "${path} is a access path"ls -l $path
elseecho "unknown file"exit 1
fi

脚本测试

[root@localhost ~]# bash pathtest.sh
Please input a path:/etc/fstab
/etc/fstab can be visited
#
# /etc/fstab
# Created by anaconda on Tue Aug  2 21:31:19 2016
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/rhel-root   /                       xfs     defaults        1 1
UUID=ce40e87b-854d-42dc-ac50-e1309101c43d /boot                   xfs     defaults        1 2
/dev/mapper/rhel-swap   swap                    swap    defaults        0 0
/dev/cdrom/media/cdromiso9660defaults0 0
[root@localhost ~]# bash pathtest.sh
Please input a path:/dev
/dev can use 'cd' command
[root@localhost ~]# bash pathtest.sh
Please input a path:/dev/cdrom
/dev/cdrom is a access path
lrwxrwxrwx. 1 root root 3 Aug  3  2016 /dev/cdrom -> sr0
[root@localhost ~]# bash pathtest.sh
Please input a path:/hello
unknown file

7、写一个脚本，取得当前主机的主机名，判断

(1) 如果主机名为空或为localhost，或为"(none)"，则将其命名为mail.magedu.com；

(2) 否则，显示现有的主机名即可；

vim hostnametest2.sh
#!/bin/bash
#
hostname=$(hostname)
if [ -z $hostname -o $hostname == "localhost" -o $hostname == "none" ];then
hostname "mail.magedu.com" && hostname
else
echo "Current hostname is $hostname"
fi

脚本测试

[root@localhost ~]# hostname
mail.magedu.com
[root@localhost ~]# bash hostnametest2.sh
Current hostname is mail.magedu.com
[root@localhost ~]# hostname localhost
[root@localhost ~]# bash hostnametest2.sh
mail.magedu.com
[root@localhost ~]# hostname none
[root@localhost ~]# bash hostnametest2.sh
mail.magedu.com

8、写一脚本，接受一个用户名为参数；

(1) 如果用户的id号为0,则显示其为管理员；

(2) 如果用户的id号大于0且小于500, 则显示其为系统用户；

(3) 否则，则显示其为普通用户；

vim usernametest.sh
#!/bin/bash
#
read -p "Please input a username:" username
if [ -z $username ];thenecho "Usage: Please input a username"exit 1
fi
if  ! id $username &>/dev/null;then
echo "user doesn't exist"
else
userid=$(id -u $username)
if [ $userid -eq 0 ];then
echo "$username is a administrator"
elif [ $userid -gt 0 -a $userid -lt 500 ];then
echo "$username is a system user"
else
echo "$username is a normal user"
fi
fi

脚本测试

[root@localhost ~]# bash usernametest.sh
Please input a username:
Usage: Please input a username
[root@localhost ~]# bash usernametest.sh
Please input a username:jack
user doesn't exist
[root@localhost ~]# bash usernametest.sh
Please input a username:root
root is a administrator
[root@localhost ~]# bash usernametest.sh
Please input a username:postfix
postfix is a system user
[root@localhost ~]# useradd yuki
[root@localhost ~]# bash usernametest.sh
Please input a username:yuki
yuki is a normal user