pyrenamer: 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/pyrenamer - from package: pyrenamer

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

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