quantlib-config: 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/quantlib-config - from package: QuantLib-devel

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

On Debian possible default full paths are:

/usr/bin/quantlib-config - from package: libquantlib0-dev

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

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