rlxtools: 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/rlxtools - from package: texlive-context

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

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