systemd-inhibit: 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:

/bin/systemd-inhibit - from package: systemd

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

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