bwbar: 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/bwbar - from package: bwbar

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

On Debian possible default full paths are:

/usr/sbin/bwbar - from package: bwbar

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

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