select-editor: 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/select-editor - from package: sensible-utils

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

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