php5: 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 Debian possible default full paths are:

/usr/bin/php5 - from package: php5-cli

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

Error in other languages:
php5: bevel nie gevind nie
php5: comandă negăsită
php5: comando não encontrado
php5: commande introuvable
php5: command not found
php5: käsku ei ole
php5: không tìm thấy lệnh
php5: komanda nerasta
php5: Kommando nicht gefunden.
php5: kommandot finns inte
php5: komut yok
php5: nie znaleziono polecenia
php5: níor aimsíodh an t-ordú
php5: no se encontró la orden
php5: no s'ha trobat l'ordre
php5: opdracht niet gevonden
php5: parancs nem található
php5: perintah tidak ditemukan
php5: príkaz nenájdený
php5: příkaz nenalezen
php5: команда не найдена
php5: командата не е открита
php5: 命令找不到
php5: コマンドが見つかりません