gvhdl: 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/gvhdl - from package: freehdl

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

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