kni_sensor: command not found

Have You tried accessing the binary with the full path?

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/kni_sensor - from package: libkni3-examples

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