yarssr: 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/yarssr - from package: yarssr

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

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