cf-agent: 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 CentOS possible default full paths are:

/usr/sbin/cf-agent - from package: cfengine
/var/cfengine/bin/cf-agent - from package: cfengine

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/sbin/cf-agent - from package: cfengine3
/usr/lib/debug/usr/sbin/cf-agent - from package: cfengine3-dbg

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

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