di: 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/di - from package: di

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

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