opusinfo: 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/opusinfo - from package: opus-tools

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

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