designate-central: 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/bin/designate-central - from package: designate-common

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

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