wmname: 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/wmname - from package: suckless-tools

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

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