osmupdate: 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/osmupdate - from package: osmctools

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

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