sg_decode_sense: 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/sg_decode_sense - from package: sg3-utils

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

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