Create Multiple SFTP-Only Users On Linux Via Script

Let’s say you need a handful of users for testing out multiple SFTP accounts. Additionally, you do not want the users to be able to login via SSH and you want everything else about the users to be identical (ie, password, content of home directory, etc).

The following script will create 10 such users:

 
 #!/bin/bash
 
 for i in {1..10};
 do
     USER=test_t
     USER+=$i
     USER+=_1_1
     echo $USER
     GROUP=sftpusers
     echo $GROUP

     egrep "^$USER" /etc/passwd >/dev/null
     if [ $? -eq 0 ]; then
 echo "WARNING: [$USER] already exists"
         continue
     fi 
 
     PASSWORD_=Password123!
     PASSWORD_=$(perl -e 'print crypt($ARGV[0], "salty")' $PASSWORD_)
     echo $PASSWORD_

     adduser -p $PASSWORD_ $USER
     usermod -g $GROUP $USER
     usermod -s /bin/nologin $USER
     chown root:$USER /home/$USER
     chmod 755 /home/$USER
     mkdir /home/$USER/writable
     chown $USER:$GROUP /home/$USER/writable
     chmod ug+rwX /home/$USER/writable
 done; 

When we execute, we will see the following output

 # ./create-sftp-user.sh 
 test_t1_1_1
 sftpusers
 saMNhdbYqwtng
 test_t2_1_1
 sftpusers
 saMNhdbYqwtng
 test_t3_1_1
 sftpusers
 saMNhdbYqwtng
 test_t4_1_1
 sftpusers
 saMNhdbYqwtng
 test_t5_1_1
 sftpusers
 saMNhdbYqwtng
 test_t6_1_1
 sftpusers
 saMNhdbYqwtng
 test_t7_1_1
 sftpusers
 saMNhdbYqwtng
 test_t8_1_1
 sftpusers
 saMNhdbYqwtng
 test_t9_1_1
 sftpusers
 saMNhdbYqwtng
 test_t10_1_1
 sftpusers
 saMNhdbYqwtng 

We can confirm the users were created like so:

# cat /etc/passwd 
...
 test_t1_1_1:x:1002:1001::/home/test_t1_1_1:/bin/nologin
 test_t2_1_1:x:1003:1001::/home/test_t2_1_1:/bin/nologin
 test_t3_1_1:x:1004:1001::/home/test_t3_1_1:/bin/nologin
 test_t4_1_1:x:1005:1001::/home/test_t4_1_1:/bin/nologin
 test_t5_1_1:x:1006:1001::/home/test_t5_1_1:/bin/nologin
 test_t6_1_1:x:1007:1001::/home/test_t6_1_1:/bin/nologin
 test_t7_1_1:x:1008:1001::/home/test_t7_1_1:/bin/nologin
 test_t8_1_1:x:1009:1001::/home/test_t8_1_1:/bin/nologin
 test_t9_1_1:x:1010:1001::/home/test_t9_1_1:/bin/nologin
 test_t10_1_1:x:1011:1001::/home/test_t10_1_1:/bin/nologin 

Happy testing!

Resources:

• https://www.developerfiles.com/how-to-create-sftp-access-to-a-single-folder-on-linux/#:~:text=%20How%20to%20create%20SFTP%20access%20to%20a,on%20%E2%80%9C%20ChrootDirectory%20%E2%80%9D%20will%20be…%20More%20
• https://www.cyberciti.biz/tips/howto-write-shell-script-to-add-user.html