SSH to multiple machines using a batch file

I have a large number of Linux devices that i want to be able to SSH into and change the netmask. I wanted to create a batch file to do this so that i can export a list of the IP addresses and then run a batch to change the netmask.

I expected my script to be something along the lines of this:

$user = "username"
$pass = "password"

dir /b cmd.exe -arp -a>List.txt
for /f "Tokens=1 Delims= " %%a in (List.txt) do (

echo SSH <IP ADDRESS from List.txt> $user $pass
echo sudo ifconfig eth0 netmask 255.255.255.192
echo exit
)

How can i get this to work? am i going along the correct lines?

Answer

You’re very close. However, batch has some nuances that may seem counterintuitive to people used to *nix shell scripting.

Variables need to be set with the set command, and there can’t be spaces on either side of the = sign. This is because you are allowed to include spaces in variable names in batch. Seriously.

Variables are called like %var% instead of $var, but you don’t use the symbols when you’re setting the values.

You don’t need to use cmd.exe to call arp; it’s a perfectly valid batch command. Because of the way arp -a output is formatted, you’re going to want to narrow things down. Find (or findstr) is about as close as you’re going to get to grep.

set user="username"
set pass="password"

arp -a|find "Interface">List.txt

for /f "tokens=1" %%a in (List.txt) do (
    SSH %user%@%%a 'sudo ifconfig eth0 netmask 255.255.255.192'
)

It should also be noted that Windows has no SSH client natively installed, so you’re going to have to find a third-party solution for that.