x_init: 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/x_init - from package: GMT

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

On Debian possible default full paths are:

/usr/lib/gmt/bin/x_init - from package: GMT

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

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