sg_inq: 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 CentOS possible default full paths are:

/usr/bin/sg_inq - from package: sg3_utils

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/sg_inq - from package: sg3-utils

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

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