pyFAI-recalib: 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/pyFAI-recalib - from package: pyfai

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

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