debdeltas: 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/debdeltas - from package: debdelta

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

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