gitosis-run-hook: 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/gitosis-run-hook - from package: gitosis

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

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