keepnote: 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/bin/keepnote - from package: keepnote

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

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