Execute Bash script remotely via cURL

Question

I have a simple Bash script that takes in inputs and prints a few lines out with that inputs

fortinetTest.sh

read -p "Enter SSC IP: $ip " ip && ip=${ip:-1.1.1.1}
printf "\n"

#check IP validation
if [[ $ip =~ ^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
  echo "SSC IP: $ip"
  printf "\n"
else
  echo "Enter a valid SSC IP address. Ex. 1.1.1.1"
  exit
fi

I tried to upload them into my server, then try to run it via curl

I am not sure why the input prompt never kick in when I use cURL/wget.

Am I missing anything?

Answer 1

Your issue can be simply be reproduced by run the script like below

$ cat test.sh | bash
Enter a valid SSC IP address. Ex. 1.1.1.1

This is because the bash you launch with a pipe is not getting a TTY, when you do a read -p it is read from stdin which is content of the test.sh in this case. So the issue is not with curl. The issue is not reading from the tty

So the fix is to make sure you ready it from tty

read < /dev/tty -p "Enter SSC IP: $ip " ip && ip=${ip:-1.1.1.1}
printf "\n"

#check IP validation
if [[ $ip =~ ^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
  echo "SSC IP: $ip"
  printf "\n"
else
  echo "Enter a valid SSC IP address. Ex. 1.1.1.1"
  exit
fi

Once you do that even curl will start working

vagrant@vagrant:/var/www/html$ curl -s localhost/test.sh | bash
Enter SSC IP:  2.2.2.2

SSC IP: 2.2.2.2

Answer 2

With the curl ... | bash form, bash's stdin is reading the script, so stdin is not available for the read command.

Try using a Process Substitution to invoke the remote script like a local file:

bash <( curl -s ... )