pyreadelf: 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/pyreadelf - from package: python-pyelftools

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

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