phpdbg: 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/phpdbg - from package: php56w-phpdbg
/usr/bin/phpdbg - from package: php70w-phpdbg

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

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