ferm: 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/ferm - from package: ferm

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

On Debian possible default full paths are:

/usr/sbin/ferm - from package: ferm

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

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