bash boundary check

noir911 · 06-21-2005, 07:37 PM

I have written a bash script to add user which will take the user name as a command line argument. But I would like to add a boundary check such that if the script is executed without a user name it will exit. Current script:

#!/bin/bash
for name in "$@"
do
echo user name is ${user}
done
echo "hello $user"
adduser $user

How am i going to add the boundary check in my script?

jlliagre · 06-21-2005, 07:44 PM

"user" is not set in your script

twantrd · 06-21-2005, 10:15 PM

What you are looking for is $#. This tells you the # of arguments given. Like so:

if [ $# -eq 0 ]; then
echo "$0: You must supply an argument!!"
exit 1
fi

However, this will accept 1 or more arguments. For this script, you'd want only 1 argument. I'll leave that to you to figure out.

-twantrd

jlliagre · 06-22-2005, 02:20 AM

Can you first explain the logic of your script ? It accepts several arguments, display all of them but use only the last one to add a user, assuming the loop is really "for user in ...", is it really what you want ?

Should you actually want to add every user name passed as an argument, here is a simpler way, which need no boundary check:

Code:

#!/bin/bash
for user
do
    echo hello "$user"
    adduser $user    
done

frandalla · 06-22-2005, 08:13 AM

I like twantrd's solution and here is my solution:

Code:

if [ "$1" == "" ]; then
echo "$0: You must supply an argument!!"
exit 1
fi

the only difference is that I'm checking only the first parameter

jlliagre · 06-22-2005, 10:09 AM

Your test is weaker as the script can be passed several arguments and the first one be an empty string.
Twantrd is doing it all right.

noir911 · 06-24-2005, 05:09 AM

ok solved.

I used

if [-z "$@"]; then
echo "...."