Convert Wav File to Asterisk GSM file format.

Create convert.sh file, which content:-

#!/bin/bash
for f in *.wav
do
OUTF=`echo "$f" | sed s/\.wav$/.gsm/g`
echo $OUTF
sox -V $f -r 8000 -c 1 $OUTF resample -ql
done

rm -rf *.wav

rm -rf *.sh

Just copy paste this Script in your wav files folder.

and open termnal go in your wav files folder using cd command.

and run this script use this command "sh convert.sh".

then all converted files are available in your wav file folder.