gfal_test_checksum: 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_test_checksum - from package: gfal-doc

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

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