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[Bash]variable does not keep its value

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# 1  
Old 08-18-2009
[Bash]variable does not keep its value
Hello all,

I have this shell script, but do not understand why the variables inside the if block does not keep its value outside. Is it because of the pipe ? How can i fix this problem ?
Thank you for helping.

Code:
local alarm=""
        local num_alarm=0
        local -a alarms
        cat $alr | while read line ; do
                alarm_message_reception=$(echo "$line" | grep "Alarm message reception")
                if [ -z "$alarm_message_reception" ] ; then
                        alarm="${alarm} ${line}"
                else
                        alarms[$num_alarm]=$alarm
                        num_alarm=$(($num_alarm + 1))
                fi
        done
        echo "${alarms[@]}" # does not echo anything

# 2  
Old 08-18-2009
For the sake of debugging, you may want to add an echo "$alarm" before the done, thus making visible where your "alarm data" goes Smilie
# 3  
Old 08-18-2009
Code:
local alarm=""
        local num_alarm=0
        local -a alarms
        while read line ; do
                alarm_message_reception=$(echo "$line" | grep "Alarm message reception")
                if [ -z "$alarm_message_reception" ] ; then
                        alarm="${alarm} ${line}"
                else
                        alarms[$num_alarm]=$alarm
                        num_alarm=$(($num_alarm + 1))
                fi
        done < "${alr}"
        echo "${alarms[@]}" # does not echo anything

# 4  
Old 08-18-2009
Quote:
Originally Posted by dr.house
For the sake of debugging, you may want to add an echo "$alarm" before the done, thus making visible where your "alarm data" goes Smilie
Hello, i did debug the script, $alarm and $alarms do contain something inside the loop.

---------- Post updated at 05:02 PM ---------- Previous update was at 05:00 PM ----------
Quote:
Originally Posted by vgersh99
Code:
local alarm=""
        local num_alarm=0
        local -a alarms
        while read line ; do
                alarm_message_reception=$(echo "$line" | grep "Alarm message reception")
                if [ -z "$alarm_message_reception" ] ; then
                        alarm="${alarm} ${line}"
                else
                        alarms[$num_alarm]=$alarm
                        num_alarm=$(($num_alarm + 1))
                fi
        done < "${alr}"
        echo "${alarms[@]}" # does not echo anything

Thank you for that, i think it should work but cannot test it now. So the reason for ${alarms[@]} to be empty is that it was set in the process of the pipe ? Just to understand exactly the reason.
Thank you.
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