ragg2: 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/ragg2 - from package: radare2

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

Error in other languages:
ragg2: bevel nie gevind nie
ragg2: comandă negăsită
ragg2: comando não encontrado
ragg2: commande introuvable
ragg2: command not found
ragg2: käsku ei ole
ragg2: không tìm thấy lệnh
ragg2: komanda nerasta
ragg2: Kommando nicht gefunden.
ragg2: kommandot finns inte
ragg2: komut yok
ragg2: nie znaleziono polecenia
ragg2: níor aimsíodh an t-ordú
ragg2: no se encontró la orden
ragg2: no s'ha trobat l'ordre
ragg2: opdracht niet gevonden
ragg2: parancs nem található
ragg2: perintah tidak ditemukan
ragg2: príkaz nenájdený
ragg2: příkaz nenalezen
ragg2: команда не найдена
ragg2: командата не е открита
ragg2: 命令找不到
ragg2: コマンドが見つかりません