Bash Script : Read a file containing IP and run script - linux

Question

I have created a useradd script in bash which is running manually(ive to copy script on remote host and run the script).
i want that script to read a host.txt file,where ill mention the ip's on which it must run by login into the remote host
#!/bin/bash
# Unlock the crtical directory for modification
chattr -i /etc/passwd
chattr -i /etc/shadow
chattr -i /etc/group
chattr -i /etc/gshadow
chattr -i /etc/ssh/sshd_config
#Script to Add User
read -p 'Please Enter The Username To Add: ' name
echo "$name" > /tmp/userlist.txt
clear
echo -e "Hello $name\nYour Name Is Added To The List."
userfile=/tmp/userlist.txt
username=$(cat /tmp/userlist.txt | tr 'A-Z' 'a-z')
for user in $username
do
useradd $user -N -s /bin/bash
usermod -aG sudo $user
passwd $user
echo "AllowUsers ${user}" >> /etc/ssh/sshd_config \\Prefix the line with # if username is hard coded
#sed -i 's/tui/tui <hard coded username>/g' /etc/ssh/sshd_config \\remove # if the user is hard coded
#sed -i 's/<hard coded username>.*<hard coded username>/<hard coded username>/g' /etc/ssh/sshd_config \\remove # if the user is hard coded
#sed -i 's/tui/tui <hard coded username>/g' /etc/security/access.conf \\remove # if the user is hard coded
done
echo "=================================="
echo "User $name Have Been Created."
echo "=================================="
tail /etc/passwd | cut -d: -f1
#lock the crtical directory for modification
chattr +i /etc/passwd
chattr +i /etc/shadow
chattr +i /etc/group
chattr +i /etc/gshadow
chattr +i /etc/ssh/sshd_config
systemctl restart ssh

Answer 1

Lets say you have a file of IP's called ip.txt
while IFS= read -r dest; do
scp useradd.sh "root#$dest:remote/path/"
ssh root#$dest "/bin/bash remote/path/useradd.sh"
done <ip.txt
If root is not available to login (recommended) then substitute with the correct user and than add sudo to the command.
This assumes the login is done via a key file and does not have a password.
If the file is already on the host then skip the scp stage - or you can use xargs like
cat ip.txt | xargs -I{} ssh user#{} sudo remote/path/useradd.sh
Or - I can recommend using ansible.