jack-scope: 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/jack-scope - from package: jack-tools

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

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