ifstatus: 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/sbin/ifstatus - from package: ifstatus

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

On Debian possible default full paths are:

/usr/sbin/ifstatus - from package: ifplugd

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

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