Add and delete a specified number of users in batches

A for loop syntax

for((initial value; loop control condition; variable change))

do

program

done

 

Second instance 1

#!/bin/bash

s=0

for (( i=1;i<=100;i=i+1 ))

do

s=$(( $s+$i ))

done

echo $s

 

Three examples 2

#!/bin/bash

read -p "please input user name" -t 30 name

read -p "please input number of users:" -t 30 num

read -p "please input the password of users:" -t 30 pass

if [ ! -z "$name" -a ! -z "$num" -a ! -z "$pass" ]

then

y=$(echo $num | sed 's/[0-9]//g')

if [ -z "$y" ]

then

for((i=1;i<=$num;i=i+1))

do

/usr/sbin/useradd $name$i &>/dev/null

echo $pass|/usr/bin/passed --stdin $name$i &>/dev/null

done

be

be

 

Four examples 3

#!/bin/bash

for i in $(cat /etc/passwd |grep /bin/bash|grep -v root |cut -d ":" -f1)

do

echo $i

userdel -r $i

done