shell脚本练习

1、分别求出一百以内的奇数和偶数之和

#!/bin/bash
#
declare -i EVENSUM=0
declare -i OODSUM=0
for i in {1..100}; do
        if [ $[$i%2] -eq 0 ]; then
                let EVENSUM+=$i
        else
                let ODDSUM+=$i
        fi  
done
echo "ODDSUM is $ODDSUM"
echo "EVENSUM is $EVENSUM"

 

2、添加用户：密码同用户名；但要求只要用户存在时才添加

#/bin/bash

#

if [ $# -lt 1 ] ; then

                echo "Usage:$0 arg"

elif [ $1 == '--add' -o $1 == '-a' ] ;then

                for i in `echo $2 | sed 's@,@@g'` ; do

                                if id $i&> /dev/null;then

                                               echo "user $i exists!"

                                else   

                                               useradd $i

                                               echo $i | passwd--stdin $i &>/dev/null

                                               echo "add user $i success!"

                                fi     

                done   

elif [ $1 == '--del' -o $1 == '-d' ] ;then

                for i in `echo $2 | sed 's@,@@g'` ; do

                               if id $i&> /dev/null;then

                                               userdel -r $i

                                               echo "del user $i success!"

                                else   

                                                echo "user $i notexists!"

                                fi     

                done   

else

                echo "Unknownoptions!"

fi