sa-learn-cyrus: 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

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/sbin/sa-learn-cyrus - from package: sa-learn-cyrus

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