gptsync: 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/sbin/gptsync - from package: anaconda

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

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