wader-core-ctl: 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/bin/wader-core-ctl - from package: wader-core

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

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