tgtd: 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/sbin/tgtd - from package: scsi-target-utils

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

On Debian possible default full paths are:

/usr/sbin/tgtd - from package: tgt

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

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