radicale: 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/radicale - from package: radicale

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

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