Mine
public text v1 · immutableexten => s,1,NoOp()
exten => s,n,Set(LINE_NUMBER=5)
exten => s,n,While($[${LEN(${SHELL(tr "\\\n"\, "&" < ${PWD}/msg${ARG1}.txt \| cut -d \\\& -f ${LINE_NUMBER})})} > 1])
exten => s,n,Set(DATA=${SHELL(tr "\\\n"\, "&" < ${PWD}/msg${ARG1}.txt \| cut -d \\\& -f ${LINE_NUMBER})})
exten => s,n,Set(${CUT(DATA,=,1)}=${CUT(DATA,=,2)})
exten => s,n,Set(LINE_NUMBER=$[${LINE_NUMBER} + 1])
exten => s,n,EndWhile()