git-flow: 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/git-flow - from package: gitflow

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

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