rusers: 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 CentOS possible default full paths are:

/usr/bin/rusers - from package: rusers

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/rusers - from package: rusers

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

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