bfgminer: 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/bfgminer - from package: bfgminer

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

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