bossac: 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/bossac - from package: bossa-cli

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

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