until loop

ppatryk · 11-22-2011, 05:44 PM

hey, lookin for some advice, I am getting the user to input a letter, A or B, I only want the user to type in A or B, so how would I make my scirpt to check if thats the input and return and error if its something else until the user types in A or B.
many thanks

corp769 · 11-22-2011, 05:49 PM

What programming language are you using? Or are you using bash scripting? You need to be more specific when asking questions like this.

ppatryk · 11-22-2011, 05:52 PM

hi, sorry, i am using bash scipting

AnanthaP · 11-22-2011, 06:03 PM

Pseudo code:
While not A and not B
Do
Get input
If input is not A and input is not B then
Message
Fi
Done

ppatryk · 11-22-2011, 06:07 PM

source code any chance plz?

corp769 · 11-22-2011, 06:47 PM

How will you learn if we do it for you?

grail · 11-22-2011, 06:54 PM

Or at least tell us what part of the pseudo code you do not know how to do or understand?

basica · 11-22-2011, 07:14 PM

Do you have any familiarity with programming? As others mentioned you need to do a couple of things:

ask the question and input the data
check the input and if it doesn't match what is requested, repeat the question

Off the top of my head, it might look like this in BASH (will have to double check to be sure though..)

use while [$variable !=] to set the condition
use do to start the loop
use echo to ask the question
use read to store the input into a variable, i.e read variable
use done to finish it

corp769 · 11-22-2011, 08:33 PM

Quote:

Originally Posted by basica

Do you have any familiarity with programming? As others mentioned you need to do a couple of things:

ask the question and input the data
check the input and if it doesn't match what is requested, repeat the question

Off the top of my head, it might look like this in BASH (will have to double check to be sure though..)

use while [$variable !=] to set the condition
use do to start the loop
use echo to ask the question
use read to store the input into a variable, i.e read variable
use done to finish it

He/She hit the nail on the head..... And besides the general questions and such, have you tried anything on your own as far as writing the script?

ppatryk · 11-23-2011, 09:48 AM

hey, thanks for the replies, I have wrote a bit of code, its doesnt use while, could someone help me finish it or advice what to do?

read answer
if [ $answer = "w" ]
then
find ~/folder.....
else
echo "Please type answer again"
until
[$answer = "w"]

grail · 11-23-2011, 10:41 AM

So what seems to be the problem with what you have so far?

It is not necessarily the most elegant but you seem to be on the right track.

ppatryk · 11-23-2011, 11:00 AM

im getting an syntax error - unexpected end of file, any help appreciated, thanks

corp769 · 11-23-2011, 11:04 AM

Quote:

Originally Posted by ppatryk

im getting an syntax error - unexpected end of file, any help appreciated, thanks

Could you post the full code you have, using code tags?

ppatryk · 11-23-2011, 01:38 PM

yes of course -

echo "What file would you like - w-word, s-spreadsheet"
read answer
if [answer = "w" ]
then
find ~/folder...............
else
echo "Only type in w or s"
until
[$answer = "w"]

then same thing again but with the letter "s".

thanks

grail · 11-24-2011, 01:01 AM

Read http://tldp.org/LDP/abs/html/testconstructs.html for the correct format of an 'if' statement

Read http://tldp.org/LDP/abs/html/loops1.html for the correct format for an 'until' loop

Also, each time you reference a variable you need to place $ in front of it to get the data stored in it.

And we are guessing you know the find command would never work as shown.