uuidgen: 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/uuidgen - from package: util-linux-ng

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

On Debian possible default full paths are:

/usr/bin/uuidgen - from package: uuid-runtime

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

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