cdinfo: 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/cdinfo - from package: cdtool

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

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