blendsquare: 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/blendsquare - from package: piglit

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

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