renattach: 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/renattach - from package: renattach

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

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