gpsdecode: 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/gpsdecode - from package: gpsd-clients

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

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