gitwhich: 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/gitwhich - from package: gnuit

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

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