Shell Programming and Scripting

Hi All, thanks in advance for any help you can give me.

I'm trying to get some error checking of a username in my shell script. While I have that part under control, at the moment my script just exits if the username entered doesn't match the correct syntax.

I've been googling to try and figure it out but I'm missing something. I can get an endless loop of my 'echo' statements but I go no further. I'm sure it's something stupidly simple but I just can't pick it.

This is part of the script I have so far:

Code:

echo -n "Enter Username (e.g. abcd1234): "
read username
echo "Entered Username:" $username

if
echo "$username" | grep -o "[wiki]:alpha:[/wiki]\{4\}[0-9]\{4\}"
     then
             echo good username
     else
             echo bad username
             exit(65)
fi

I also want to know if the exit65 is the correct usage.

-- Adarii

Have a look at the script in this thread which does a similar thing:

https://www.unix.com/shell-programmin...d-command.html

The correct syntax for the exit to return a code 64 would just be exit 65.

Thanks so much for your prompt response, unfortunately I'm totally script newbie and I'm pretty lost when I look at that guys script

I figured it would be some kind of while loop waiting for a certain criteria to be met before it exited out but how I set that criteria is wehre I'm lost.

If anyone who can help would explain it in longhand that'd be great. I'll keep looking in the mean time

Hope everyone has a good weekend

Try this (untested):

Code:

until echo "$username" | grep -o "[[:alpha:]]\{4\}[0-9]\{4\}"
do
    echo -n "Enter Username (e.g. abcd1234): "
    read username
    echo "Entered Username:" $username
done

Absolutely perfect thankyou so much

Now I know about the 'until' command

Woohoo!