stopwatch: 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/stopwatch - from package: stopwatch

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

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