gbp-pull: 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/gbp-pull - from package: git-buildpackage

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

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