gsx: 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/gsx - from package: ghostscript-gtk

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