find: 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:

/bin/find - from package: findutils
/usr/bin/find - from package: findutils

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

On Debian possible default full paths are:

/usr/bin/find - from package: findutils

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

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