oneko: 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/oneko - from package: oneko

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

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