date: command not found

Have You tried accessing the binary with the full path?

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/date - from package: coreutils

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

On Debian possible default full paths are:

/bin/date - from package: coreutils
/usr/lib/plan9/bin/date - from package: 9base

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