hdfed: 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/bin/hdfed - from package: hdf

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

On Debian possible default full paths are:

/usr/bin/hdfed - from package: hdf4-tools

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

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