gfal-rename: 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/gfal-rename - from package: gfal2-util

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

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