envext: 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/envext - from package: csound-utils

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

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