hdfcomp: 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/hdfcomp - from package: hdf

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

On Debian possible default full paths are:

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

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

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