Whiptail: How can I handle an error when a gauge is running?

Question

Here is a for loop, which is running a regular Whiptail gauge. I this loop, a command might throw an error and I would like to display a message box --msgbox displaying the error. After that, I could like the script to continue it's way like the error never happened.

Here is an oversimplified code as an example. Here is it's behavior and the code:

• A for list is iterating on an array with 3 numbers and 1 letter.
• For the 2 first numbers, a command using them is executed and a gauge is increasing by 25%.
• For the letter, the command will fail, and I would like to display a --msgbox with the error waiting me to press enter
• For the last number, the same behavior than for the 2 others.

#!/bin/bash

array=("1" "2" "A" "3")

i=0
for element in "${array[@]}"; do
        command $element #This command will fail with any non int value.
        echo "XXX"
        echo $(expr 100 / 4 \* $i)
        echo ${array[$i]}
        echo "XXX"
        i=$((i+1))
        sleep 1
done | whiptail --title "Gauge" --gauge "Wait" 10 80 0

I have already tried few things like command $element || whiptail --title "Exception" --msgbox "Error!" 10 80. However, as the whiptail for the message box is in the loop for the gauge, the output is broken.

The problem is maybe coming from my design?

Thank you for your help :)

Answer 1

Even though it's been a while that this has been asked, you can output to a different output descriptor. In my case, I output to a separate log file like so:

#!/bin/bash

array=("1" "2" "A" "3")

i=0
for element in "${array[@]}"; do
        command $element #This command will fail with any non int value.
        echo "XXX" >> logs.log
        echo $(expr 100 / 4 \* $i)
        echo ${array[$i]} >> logs.log
        echo "XXX" >> logs.log
        i=$((i+1))
        sleep 1
done | whiptail --title "Gauge" --gauge "Wait" 10 80 0