lwatch: 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/lwatch - from package: lwatch

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

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