The bash program below is a (test) program to test the values of a USB
interface card.

The lines in front are only for clarification.

When an input port on the USB card gets activated, then the variable
digital_inputs changes (in line 11).
I checked that with line 12
The next time the while statement executes (in line 8) it should be false,
and the while loop should stop.

This doesn't happen. :(

What is my mistake? (don't get a syntax error)



1#!/bin/bash
2
3 digital_inputs=0
4 portstatus_dec=0
5
6
7
8 while [ $digital_inputs=$portstatus_dec ];
9 do
10 sleep 1
11 digital_inputs=`k8055 -m:1 2>/dev/null | tail -1 | cut -d';' -f2`
12 echo $digital_inputs
13 done
14
15 echo "There is an alarm"

On Wed, 27 Feb 2008 21:01:49 +0100, Henk Oegema wrote:

> The bash program below is a (test) program to test the values of a USB
> interface card.
>
> The lines in front are only for clarification.
>
> When an input port on the USB card gets activated, then the variable
> digital_inputs changes (in line 11).
> I checked that with line 12
> The next time the while statement executes (in line 8) it should be
> false, and the while loop should stop.
>
> This doesn't happen. :(
>
> What is my mistake? (don't get a syntax error)
>
>
>
> 1#!/bin/bash
> 2
> 3 digital_inputs=0
> 4 portstatus_dec=0
> 5
> 6
> 7
> 8 while [ $digital_inputs=$portstatus_dec ]; 9 do

In a test, you need a space on each side of the equals sign.

> 10 sleep 1
> 11 digital_inputs=`k8055 -m:1 2>/dev/null | tail -1 | cut -d';'
> -f2` 12 echo $digital_inputs
> 13 done
> 14
> 15 echo "There is an alarm"

El Tux <nope@spamsucks.invalid>:
> On Wed, 27 Feb 2008 21:01:49 +0100, Henk Oegema wrote:
> >
> > 1#!/bin/bash
> > 2
> > 3 digital_inputs=0
> > 4 portstatus_dec=0
> > 8 while [ $digital_inputs=$portstatus_dec ];
>
> In a test, you need a space on each side of the equals sign.

And, to quote Ben at linuxgazette.net, *always* double-quote your
variables. They may be empty.

> > 10 sleep 1
> > 11 digital_inputs=`k8055 -m:1 2>/dev/null | tail -1 | cut -d';' -f2`
> > 12 echo $digital_inputs
> > 13 done
> > 14
> > 15 echo "There is an alarm"


--
Any technology distinguishable from magic is insufficiently advanced.
(*) http://blinkynet.net/comp/uip5.html Linux Counter #80292
- - http://www.faqs.org/rfcs/rfc1855.html Please, don't Cc: me.

s. keeling wrote:

>
> And, to quote Ben at linuxgazette.net, *always* double-quote your
> variables. They may be empty.
>
Yep. :)

Henk Oegema <henk@oegema.com> writes:

>The bash program below is a (test) program to test the values of a USB
>interface card.

>The lines in front are only for clarification.

>When an input port on the USB card gets activated, then the variable
>digital_inputs changes (in line 11).
>I checked that with line 12
>The next time the while statement executes (in line 8) it should be false,
>and the while loop should stop.

>This doesn't happen. :(

>What is my mistake? (don't get a syntax error)

Put spaces on either side of the = in test.




>1#!/bin/bash
>2
>3 digital_inputs=0
>4 portstatus_dec=0
>5
>6
>7
>8 while [ $digital_inputs=$portstatus_dec ];
>9 do
>10 sleep 1
>11 digital_inputs=`k8055 -m:1 2>/dev/null | tail -1 | cut -d';' -f2`
>12 echo $digital_inputs
>13 done
>14
>15 echo "There is an alarm"