bno_plot.py: 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/bno_plot.py - from package: blktrace

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

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