eu-readelf: 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/eu-readelf - from package: elfutils

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

On Debian possible default full paths are:

/usr/bin/eu-readelf - from package: elfutils

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

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