bpython: 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 CentOS possible default full paths are:

/usr/bin/bpython - from package: bpython

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/bpython - from package: bpython

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

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