cdfmoy_freq: command not found

Have You tried accessing the binary with the full path?

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/cdfmoy_freq - from package: cdftools

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