swisswatch: 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 Debian possible default full paths are:

/usr/bin/swisswatch - from package: swisswatch

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