GraphicsMagick-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/GraphicsMagick-config - from package: GraphicsMagick-devel

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

On Debian possible default full paths are:

/usr/bin/GraphicsMagick-config - from package: libgraphicsmagick1-dev

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

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