square: 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/mpich/bin/square - from package: scalasca-mpich
/usr/lib64/openmpi/bin/square - from package: scalasca-openmpi

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

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