sunbird: 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/sunbird - from package: sunbird

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

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