monitor: 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/sbin/monitor - from package: 389-ds-base
/usr/bin/monitor - from package: dmucs
/usr/share/torrus/bin/monitor - from package: torrus-common

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

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