[root@mail ~]# echo 1234568 |passwd --stdin zhangsan
Changing password for user zhangsan
passwd: all authentication tokens updated successfully.
[root@mail ~]# echo $RANDOM
31427
[root@mail ~]# echo $RANDOM
10943
[root@mail ~]# echo $RANDOM
4070
[root@mail ~]# echo $RANDOM
20273
[root@mail ~]# echo $RANDOM |md5sum
d908b56aea8ba230846e9a6a21093f86 -
[root@mail ~]# echo $RANDOM |md5sum
d6a8e0adb2607506fc0e07a53c0e1448 -
[root@mail ~]# echo $RANDOM |md5sum
c2be3c5e60858b9416a4b72cd6968a03 -
[root@mail ~]# echo $RANDOM |md5sum |cut -c 1-8
0c61bdc7
[root@mail ~]# echo $RANDOM |md5sum |cut -c 1-8
0bc8559f
[root@mail ~]# echo $RANDOM |md5sum |cut -c 1-8
b531b827
[root@mail sh]# echo {1..10}
1 2 3 4 5 6 7 8 9 10
[root@mail sh]# id zhangsan
uid=1000(zhangsan) gid=1000(zhangsan) groups=1000(zhangsan)
[root@mail sh]# id lisi
id: lisi: no such user
[root@mail sh]# id lisi
id: lisi: no such user
[root@mail sh]# echo $?
1
[root@mail sh]# ls
1.sh
[root@mail sh]# echo $?
0
For example: if the execution is successful, execute the else inside, and if the execution fails, execute the following then
#!/bin/bash
USER_LIST=./user.list #Store the user name and provide a list for deleting users in the future
USER_FILE=./user.info #Record the password corresponding to the user in the user.info file under the Dangqia directory
for USER in user{1..20};do #Create 20 users
if ! id $USER &>/dev/null; then #Determine whether the user exists, if it exists, execute else below, if it does not exist, then execute then PASS=$
( echo $RANDOM | md5sum |cut -c 1-8) &>/dev/null #Intercept 8 random passwords
useradd $USER #Create user
echo $PASS | passwd --stdin $USER &>/dev/null #Interaction-free Assign a password to the user
echo " $USER $PASS " >> $USER_FILE #Write the password corresponding to the user in a file
echo " $USER " >> $USER_LIST
echo " $USER create sucessful! " #Execute successfully and return the value
else
echo "$USER already exists!!!" #If the user already exists, return the value
fi
done
[root@mail sh]# ./1.sh
user1 create sucessful!
user2 create sucessful!
user3 create sucessful!
user4 create sucessful!
user5 create sucessful!
[root@mail sh]# ./2.sh
The user1 delete success !
The user2 delete success !
The user3 delete success !
The user4 delete success !
The user5 delete success !
#!/bin/bash
USER_LIST=$@
USER_FILE=./user.info
for USER in $USER_LIST; do
if ! id $USER &>/dev/null; then
PASS=$(echo $RANDOM | md5sum |cut -c 1-8) &>/dev/null
useradd $USER
echo $PASS | passwd --stdin $USER &>/dev/null
echo " $USER $PASS " >> $USER_FILE
echo " $USER create sucessful! "
else
echo "$USER already exists!!!"
fi
done
[root@mail sh]# ./1.sh lisi wangwu zhao
lisi create sucessful!
wangwu create sucessful!
zhao create sucessful!
#!/bin/bash
for user in `cat user.list`
do
userdel -r $user
echo "The $user delete success !"
done
#!/bin/bash
USER_FILE=./user.info
for USER in `cat user2.list`; do
if ! id $USER &>/dev/null; then
PASS=$(echo $RANDOM | md5sum |cut -c 1-8) &>/dev/null
useradd $USER
echo $PASS | passwd --stdin $USER &>/dev/null
echo " $USER $PASS " >> $USER_FILE
echo " $USER create sucessful! "
else
echo "$USER already exists!!!"
fi
done