练习1 写一个脚本，让用户输入几个文件，脚本能多将此几个文件归档压缩成一个文件。
#!/bin/bash
read -p "please input three files:" FILE1 FILE2 FILE3
read -p "please input name:" DNAME
tar -jcf /root/mscripts/cpios/${DNAME}.bz2 $FILE1 $FILE2 $FILE3
拓展： 用户自己指定压缩方式
[root@localhost mscripts]# cat lx26.sh
#!/bin/bash
read -p "please input three files:" FILE1 FILE2 FILE3
read -p "please input name:" DNAME
read -p "please input your cmios chioce:" cpios
case $cpios in
gzip)
tar -zcf /root/mscripts/cpios/${DNAME}.gz $FILE1 $FILE2 $FILE3
;;
bzip2)
tar -jcf /root/mscripts/cpios/${DNAME}.bz2 $FILE1 $FILE2 $FILE3
;;
xz)
tar -cf /root/mscripts/cpios/${DNAME}.tar $FILE1 $FILE2 $FILE3
xz /root/mscripts/cpios/${DNAME}.tar
;;
)
echo "quit..."
exit 9
esac
练习2 写一个脚本 计算1到100以内的整数和，要求用while语句。
[root@localhost mscripts]# cat lx25.sh
#!/bin/bash
declare -i I=1
declare -i SUM=0
while [ $I -le 100 ]; do
let SUM+=$I
let I++
done
echo "the sum:$SUM."
练习3 写一个脚本 每5秒种监测下某一用户是否登录系统，如果登录就退出脚本；
[root@localhost mscripts]# cat lx28.sh
#!/bin/bash
who | grep "bruce" &> /dev/null
RETU=$?
while [ $RETU -ne 0 ]; do
echo "date, user bruce no loged."
sleep 5
who | grep "bruce" &> /dev/null
RETU=$?
done
echo "user bruce has loged."
练习4 写一个脚本
1）显示一个菜单给用户
d|D shou disk usages.
m|M show memory usages.
s|S show memory usages.
) quit
2） 当用户给定选项后显示相应的内容
[root@localhost mscripts]# cat lx29.sh
#!/bin/bash
cat << EOF
d|D show disk usages.
m|M show memory usages.
s|S show swap usages.
) quit
EOF
read -p "please input your choice:" CHOICE
case $CHOICE in
d|D)
df -h ;;
m|M)
free -m | grep "Mem" ;;
s|S)
free -m | grep "Swap"
;;
)
echo "quit..."
exit 9
esac

        扩展：
         当用户选择完成，显示相应信息后，不退出；而让用户再一次选择，再次显示相应内容，除了用户使用quit；
         [root@localhost mscripts]# cat lx30.sh

#!/bin/bash
cat << EOF
d|D show disk usages.
m|M show memory usages.
s|S show swap usages.
) quit
EOF
read -p "please input your choice:" CHOICE
while [ $CHOICE != 'quit' ]; do
case $CHOICE in
d|D)
df -h ;;
m|M)
free -m | grep "Mem" ;;
s|S)
free -m | grep "Swap"
;;
)
echo "quit..."
esac
read -p "please input your choice:" CHOICE
done