jythonc: 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/jythonc - from package: jython

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

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