Exit bash script on error in loop

[Johnny Rosenberg]

Okay, now that I found that the pipe was causing the problem, I also found
the answer: PIPESTATUS. See below…


2013/9/12 Johnny Rosenberg <gurus.knugum at gmail.com>

> 2013/9/12 Tony Arnold <tony.arnold at manchester.ac.uk>
>
>> Johnny,
>>
>> On 12/09/13 19:19, Johnny Rosenberg wrote:
>> >
>> > I can't make exit work as I thought it would work…
>> >
>> > #!/bin/bash
>> >
>> > Title="Error"
>> > ERROR="Something bad happened."
>> >
>> > while [ something ]; do
>> >     if [[ something_bad ]]; then
>> >         yad --title "${Title}" \
>> >             --image=error \
>> >             --text "${ERROR}" \
>> >             --no-buttons \
>> >             --timeout 5 &
>> >         exit 1
>> >     fi
>> > done
>> > more_statements
>> >
>> > # End of code
>> >
>> > The problem is that even if something_bad happens, more_statements are
>> > executed. The yad error messages is displayed as expected, though.
>> >
>> > (yad is a dialogue, similar to zenity, or even a zenity fork, I think –
>> > yad=Yet Another Dialogue)
>> >
>> > So it seems like only the loop is exited when exit 1 is executed, not
>> > the whole script. So how can I exit the whole script if something bad
>> > happens inside a loop? I'd prefer a solution that doesn't make it
>> > necessary to rewrite the script from scratch…
>>
>> Odd. The following works for me. I'm on 13.04. Cannot find yad in the
>> repositories. Where did you get it from?
>
>
> I don't remember, but I think I compiled it from source.
>
>
>> And are you definitely using
>> bash for your script?
>>
>
> I'm on Ubuntu 12.04 and I didn't change anything like that.
>
>
>>
>> #!/bin/bash
>>
>> i=4
>> while [ "$i" -gt "0" ]; do
>>     echo "$i - Hello"
>>     if [ "$i" -eq "2" ]; then
>>         zenity --error --text "Oh no! i=3"
>>         exit 1
>>     fi
>>     let i=i-1
>> done
>> echo "Oops!"
>>
>
>
> This one works for me too. I also replaced zenity with yad, and it still
> works.
>
> I did some more experiments and I found that it's my pipe to a yad
> progress bar that cause the problem. Unfortunately I didn't include it in
> my example, but here's another example, which I included in a reply to
> another reply:
>
> #!/bin/bash
>
> WaitTime=10
> TargetPath="This/path/does/not/exist"
>
> if [ ! -e "${TargetPath}" ]; then
>     Time=0
>     StartTime=$(date +%s%N)
>
>     while [ ! -e "${TargetPath}" ]; do
>         sleep .1
>         Time=$(($(date +%s%N)-StartTime))
>         if [[ Time -ge WaitTime*10**9 ]]; then
>             yad --title "Folder missing" \
>                 --image=error \
>                 --text "Your device is not connected." \
>                 --no-buttons \
>                 --timeout 5
>             exit 1
>         fi
>         echo "$((Time/10**7/WaitTime))"
>         Seconds=$((WaitTime-Time/10**9))
>         MM=$((Seconds/60))
>         SS=$((Seconds-MM*60))
>         echo \#$(printf "%s %d:%02d." "Time to connect your device:" "$MM"
> "$SS")
>     done | \
>     yad --progress \
>         --title="Folder missing" \
>         --image=time \
>         --percentage=0 \
>         --auto-close
> fi
>

Now, it seems like I need to check for the pipe status, for instance:
[[ PIPESTATUS[0] -ne 0 ]] && exit ${PIPESTATUS[0]}

or

[ ${PIPESTATUS[0]} -ne 0 ] && exit ${PIPESTATUS[0]}

or

[[ PIPESTATUS[0] != 0 ]] && exit ${PIPESTATUS[0]}

or

[[ PIPESTATUS[0] ]] && exit ${PIPESTATUS[0]}

and so on…

Thanks for replying and making me think in the right direction!


Johnny Rosenberg


>
> yad --image="info" \
>     --title="Another dialogue" \
>     --text="You shouldn't see this dialogue"
>
> # End of code
>
> Remove the yad progress thing and it works. The problem is that I WANT the
> progress thing…
> So I guess the pipe is the problem here somehow, but how and what to do
> about it?
>
>
> Johnny Rosenberg
>
>
>>
>>
>> Regards,
>> Tony.
>> --
>> Tony Arnold,                        Tel: +44 (0) 161 275 6093
>> Head of IT Security,                Fax: +44 (0) 705 344 3082
>> University of Manchester,           Mob: +44 (0) 773 330 0039
>> Manchester M13 9PL.                 Email: tony.arnold at manchester.ac.uk
>>
>> --
>> ubuntu-users mailing list
>> ubuntu-users at lists.ubuntu.com
>> Modify settings or unsubscribe at:
>> https://lists.ubuntu.com/mailman/listinfo/ubuntu-users
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ubuntu.com/archives/ubuntu-users/attachments/20130912/198219a2/attachment.html>