ikarus: 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/ikarus - from package: ikarus

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

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