cmdtest: 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/cmdtest - from package: cmdtest

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

On Debian possible default full paths are:

/usr/bin/cmdtest - from package: cmdtest

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

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