Bash script inputting multiple variables

Question

I use a simple shell script to block IP addresses that just substitutes my input (an IP) for a variable in an iptables, IPFW, etc. (depending on which platform on) command, but they all basically follow this format:

read -p "IP to Block: " ip

ipfw add deny ip from $ip to any

Is it possible to simply execute, sequentially, a group of user-defined variables. For example, three IP addresses, and have the script execute, basically, three times for each of the variables, but limit my input to a single prompt (being asked to input one time)?

Explosion Pills · Accepted Answer · 2013-02-07 05:58:51Z

1

Sounds like you want to do something like this:

for ip in $@; do
    ipfw add deny ip from $ip to any
done

I'm not sure if that's the exact usage of ipfw, but $@ is every word in a command except the first, so it would work with:

your-script-name 1.2.3.4   1.3.4.5   1.4.5.6

answered Feb 7, 2013 at 5:58

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2 Comments

tony_perkis666 Over a year ago

Excellent, thank you. For IPFW, as long as each variable prints as a single IP address for each instance of the command, then this should suffice for the level of firewall administration that the script is intended to cover.

244an Over a year ago

You can use it with read with prompt also, in the script read -p "IPs to Block (separate with space): " ips and then for ip in $ips; do ... instead. And then run it without arguments.

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