attrib-assignments: 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/lib64/piglit/bin/attrib-assignments - from package: piglit

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

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