cdfsmooth: 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/cdfsmooth - from package: cdftools

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

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