pyFAI-average: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/pyFAI-average - from package: pyfai

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