arm: 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/arm - from package: tor-arm

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

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