made the bash script code shellcheck compatible, replaced obsolete statements
made the bash script code shellcheck compatible, replaced obsolete statements

freedomboxtwh/Plinth,jvalleroy/plinth-debian,vignanl/Plinth,kkampardi/Plinth,kkampardi/Plinth,kkampardi/Plinth,kkampardi/Plinth,harry-7/Plinth,kkampardi/Plinth,harry-7/Plinth,vignanl/Plinth,freedomboxtwh/Plinth,harry-7/Plinth,jvalleroy/plinth-debian,jvalleroy/plinth-debian,freedomboxtwh/Plinth,vignanl/Plinth,jvalleroy/plinth-debian,vignanl/Plinth,vignanl/Plinth,freedomboxtwh/Plinth,jvalleroy/plinth-debian,harry-7/Plinth,freedomboxtwh/Plinth,harry-7/Plinth