debi: 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/debi - from package: devscripts

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

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