red: 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/red - from package: ed

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

On Debian possible default full paths are:

/bin/red - from package: ed

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

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