gfsview: 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/gfsview - from package: gfsview

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

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