练习1 写一个脚本，利用RANDOM生成10个随机数，并找出其中的最大值最小值 [root@localhost mscripts]# cat lx20.sh #!/bin/bash declare -i MIN=0 declare -i MAX=0 for I in {1..10}; do declare -i N=echo $RANDOM [ $I -eq 1 ] && MIN=$RANDOM if [ $I -le 9 ]; then echo -n "$N," else echo "$N" fi if [ $N -gt $MAX ]; then MAX=$N fi if [ $N -lt $MIN ]; then MIN=$N fi done echo -e "MAX is $MAX.\nMIN is $MIN"

练习2 写一个脚本 ，跟三个整数； 并比较三个整数的大小，找出最大值与最小值；

[root@localhost mscripts]# cat lx21.sh #!/bin/bash declare -i MAX=0 declare -i MIN=$1 for I in {$1,$2,$3}; do if [ $I -gt $MAX ]; then MAX=$I fi if [ $I -lt $MIN ]; then MIN=$I fi done echo -e "MAX is $MAX. \nMIN is $MIN." 练习3 写一个脚本 接受一个选项--Add,--Del，后面跟参数：user1,user2,user10 --Add:添加用户user1,user10 --Del: 删除用户user1,user10 其他：退出 [root@localhost mscripts]# cat lx22.sh #!/bin/bash if [ $# -lt 2 ]; then echo "please input two arguments.." exit 0 fi if [ $1 = '--add' ]; then for I in echo $2 | sed 's@,@ @g'; do if id $I &> /dev/null; then echo "user $I exist" else useradd $I &> /dev/null echo "$I" | passwd --stdin $I &> /dev/null echo "user $I have been added." fi done elif [ $1 = '--del' ]; then for I in echo $2 | sed 's@,@ @g'; do if ! id $I &> /dev/null; then echo "user $I not exist." else userdel -r $I &> /dev/null echo "user $I have been deleted." fi done else echo "quit..." exit 9 fi