exportfs: 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/exportfs - from package: nfs-utils

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

On Debian possible default full paths are:

/usr/sbin/exportfs - from package: nfs-kernel-server

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

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