cdfvar: 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/cdfvar - from package: cdftools

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

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