tgtimg: 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/tgtimg - 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/tgtimg - from package: tgt

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

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