greadelf: 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/greadelf - from package: greadelf

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

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