byacc: 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/byacc - from package: byacc

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

On Debian possible default full paths are:

/usr/bin/byacc - from package: byacc

You may install the required package with command apt-get install {package}

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