supervisor: 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/supervisor - from package: nodejs-supervisor

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

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