re: 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/re - from package: re

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

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