loginctl: command not found

Have You tried accessing the binary with the full path?

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:

/bin/loginctl - from package: systemd

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