debugclient: 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/debugclient - from package: php54w-pecl-xdebug
/usr/bin/debugclient - from package: php55w-pecl-xdebug
/usr/bin/debugclient - from package: php56w-pecl-xdebug
/usr/bin/debugclient - from package: php70w-pecl-xdebug
/usr/bin/debugclient - from package: php-pecl-xdebug

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

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