br_pmfetch: 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/br_pmfetch - from package: ruby-bio

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

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