ksplice-apply: 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 Debian possible default full paths are:

/usr/sbin/ksplice-apply - from package: ksplice

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

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