cdfinfo: 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/cdfinfo - from package: cdftools

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

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