rarun2: 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/rarun2 - from package: radare2

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

Error in other languages:
rarun2: bevel nie gevind nie
rarun2: comandă negăsită
rarun2: comando não encontrado
rarun2: commande introuvable
rarun2: command not found
rarun2: käsku ei ole
rarun2: không tìm thấy lệnh
rarun2: komanda nerasta
rarun2: Kommando nicht gefunden.
rarun2: kommandot finns inte
rarun2: komut yok
rarun2: nie znaleziono polecenia
rarun2: níor aimsíodh an t-ordú
rarun2: no se encontró la orden
rarun2: no s'ha trobat l'ordre
rarun2: opdracht niet gevonden
rarun2: parancs nem található
rarun2: perintah tidak ditemukan
rarun2: príkaz nenájdený
rarun2: příkaz nenalezen
rarun2: команда не найдена
rarun2: командата не е открита
rarun2: 命令找不到
rarun2: コマンドが見つかりません