pirum: 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/pirum - from package: php-pirum-Pirum

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

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