obnam: 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/obnam - from package: obnam

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

On Debian possible default full paths are:

/usr/bin/obnam - from package: obnam

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

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