xev: 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/xev - from package: xorg-x11-utils

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

On Debian possible default full paths are:

/usr/bin/xev - from package: x11-utils

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

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