birdcl: 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/sbin/birdcl - from package: bird

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

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