xrdcopy: 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/xrdcopy - from package: xrootd-client

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

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