pygeis: 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/pygeis - from package: geis-tools

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