dulwich: 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/dulwich - from package: python-dulwich

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

On Debian possible default full paths are:

/usr/bin/dulwich - from package: python-dulwich

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

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