rtcanrecv: command not found

Have You tried accessing the binary with the full path?

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/rtcanrecv - from package: xenomai-runtime

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