Bash脚本：选项-案例：多个数字的范围

Question

I'm working on a script in Linux Bash, with different kinds of options to use. Basically, the program is going to ping to the given ip-address.

Now, I want to enable the user to write a range of ip-adresses in the terminal, which the program then will ping.

Fe: bash pingscript 25 - 125

the script will then ping all the addresses between 192.168.1.25 and 192.168.1.125.

That's not to hard, I just need to write a little case with

[0-9]-[0-9] ) ping (rest of code)

Now the problem is: this piece of code will only enable me to ping numbers of fe. 0 - 9 and not 10 - 25 .

For that I'd need to write: [0-9][0-9]-[0-9][0-9] (fe: ping 25 - 50)

But then there's the possibility of having 1 number on one side and 2 on the other: [0-9]-[0-9][0-9] (fe: ping 1 - 25)

or: [0-9]-[0-9][0-9][0-9] (fe: ping 1 - 125)

and so on... That means there're a lot of possibilities. There's probably another way to write it, but how?

I don't want any letters to be in the arguments, but I can't start with that (loop-through system).

Answer 1

How about that:

for i in 192.168.1.{25..125}; do ping -qnc1 $i; done

Or in a script with variables as arguments:

for i in $(seq -f "192.168.1.%g" $1 $2); do ping -qnc1 -W1 $i; done

Where the first argument is the number where to begin and the second argument where to end. Call the script like this:

./script 25 125

The ping options:

• -q : that ping doesn't print a summary
• -n : no dns lookups
• -c1 : Only send 1 package
• -W1 : timeout to 1 second (can be increased of cource)

Answer 2

You can use extended pattern matching in your script by enabling the extglob shell option:

shopt -s extglob

So you can use braces with a + quantifier like this:

#!/bin/bash

shopt -s extglob

case $1 in
+([0-9])-+([0-9]) )
    # do stuff
    ;;
esac