gfal-chmod: 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-chmod - from package: gfal2-util

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

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