quearcode: command not found

Have You tried accessing the binary with the full path?

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/quearcode - from package: quearcode

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