faust2sigviewer: 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/faust2sigviewer - from package: faust

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

Error in other languages:
faust2sigviewer: bevel nie gevind nie
faust2sigviewer: comandă negăsită
faust2sigviewer: comando não encontrado
faust2sigviewer: commande introuvable
faust2sigviewer: command not found
faust2sigviewer: käsku ei ole
faust2sigviewer: không tìm thấy lệnh
faust2sigviewer: komanda nerasta
faust2sigviewer: Kommando nicht gefunden.
faust2sigviewer: kommandot finns inte
faust2sigviewer: komut yok
faust2sigviewer: nie znaleziono polecenia
faust2sigviewer: níor aimsíodh an t-ordú
faust2sigviewer: no se encontró la orden
faust2sigviewer: no s'ha trobat l'ordre
faust2sigviewer: opdracht niet gevonden
faust2sigviewer: parancs nem található
faust2sigviewer: perintah tidak ditemukan
faust2sigviewer: príkaz nenájdený
faust2sigviewer: příkaz nenalezen
faust2sigviewer: команда не найдена
faust2sigviewer: командата не е открита
faust2sigviewer: 命令找不到
faust2sigviewer: コマンドが見つかりません