istgt: 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/sbin/istgt - from package: istgt

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

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