jetring-apply: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/jetring-apply - from package: jetring

You may install the required package with command apt-get install {package}

Error in other languages:
jetring-apply: bevel nie gevind nie
jetring-apply: comandă negăsită
jetring-apply: comando não encontrado
jetring-apply: commande introuvable
jetring-apply: command not found
jetring-apply: käsku ei ole
jetring-apply: không tìm thấy lệnh
jetring-apply: komanda nerasta
jetring-apply: Kommando nicht gefunden.
jetring-apply: kommandot finns inte
jetring-apply: komut yok
jetring-apply: nie znaleziono polecenia
jetring-apply: níor aimsíodh an t-ordú
jetring-apply: no se encontró la orden
jetring-apply: no s'ha trobat l'ordre
jetring-apply: opdracht niet gevonden
jetring-apply: parancs nem található
jetring-apply: perintah tidak ditemukan
jetring-apply: príkaz nenájdený
jetring-apply: příkaz nenalezen
jetring-apply: команда не найдена
jetring-apply: командата не е открита
jetring-apply: 命令找不到
jetring-apply: コマンドが見つかりません