keepassx2: 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/keepassx2 - from package: keepassx2

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

Error in other languages:
keepassx2: bevel nie gevind nie
keepassx2: comandă negăsită
keepassx2: comando não encontrado
keepassx2: commande introuvable
keepassx2: command not found
keepassx2: käsku ei ole
keepassx2: không tìm thấy lệnh
keepassx2: komanda nerasta
keepassx2: Kommando nicht gefunden.
keepassx2: kommandot finns inte
keepassx2: komut yok
keepassx2: nie znaleziono polecenia
keepassx2: níor aimsíodh an t-ordú
keepassx2: no se encontró la orden
keepassx2: no s'ha trobat l'ordre
keepassx2: opdracht niet gevonden
keepassx2: parancs nem található
keepassx2: perintah tidak ditemukan
keepassx2: príkaz nenájdený
keepassx2: příkaz nenalezen
keepassx2: команда не найдена
keepassx2: командата не е открита
keepassx2: 命令找不到
keepassx2: コマンドが見つかりません