echo gammu environment variable

Question

I am trying to write a script that uses some environtment variables that are set by the sms sending/receiving program gammu. These variables are set at the moment when messages are received/sent and are not accessible otherwise. This means that the script must run by the daemon to make use of these variables. This isn't a problem, but actually accessing these! This is the example script I am trying to run from withing gammu.

#!/bin/sh
for i in `seq $SMS_MESSAGES` ; do
        echo SMS_"${i}"_NUMBER SMS_"${i}"_TEXT >> smslog.dat
done

Basically I want to make a log of all the messages received. However with the above script all I get is SMS_1_NUMBER SMS_1_TEXT. How can I get the values stored in these variables?

Answer 1

Your script could do just

env | grep -E '^SMS_.*_(NUMBER|TEXT)=' >>smslog.dat

Alternatively,

i=1

while [ "$i" -le "$SMS_MESSAGES" ]; do
    printf 'Message %d number = "%s"\n' "$i" "$( eval printf '%s' "\$SMS_${i}_NUMBER" )"
    printf 'Message %d text   = "%s"\n' "$i" "$( eval printf '%s' "\$SMS_${i}_TEXT" )"

    i=$(( i + 1 ))
done >>smslog.dat

To be sure that you write to smslog.dat in the correct location, either use cd in your script to the correct directory, or specify smslog.dat with its full path.