xlsatoms: 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/xlsatoms - 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/xlsatoms - from package: x11-utils

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

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