cyclictest: 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/cyclictest - from package: rt-tests

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

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