pyFAI-waxs: 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
/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/pyFAI-waxs - from package: pyfai

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