idle: 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:

/usr/bin/idle - from package: python-tools

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

On Debian possible default full paths are:

/usr/bin/idle - from package: idle

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

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