sstm8: 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/sstm8 - from package: sdcc-ucsim

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

Error in other languages:
sstm8: bevel nie gevind nie
sstm8: comandă negăsită
sstm8: comando não encontrado
sstm8: commande introuvable
sstm8: command not found
sstm8: käsku ei ole
sstm8: không tìm thấy lệnh
sstm8: komanda nerasta
sstm8: Kommando nicht gefunden.
sstm8: kommandot finns inte
sstm8: komut yok
sstm8: nie znaleziono polecenia
sstm8: níor aimsíodh an t-ordú
sstm8: no se encontró la orden
sstm8: no s'ha trobat l'ordre
sstm8: opdracht niet gevonden
sstm8: parancs nem található
sstm8: perintah tidak ditemukan
sstm8: príkaz nenájdený
sstm8: příkaz nenalezen
sstm8: команда не найдена
sstm8: командата не е открита
sstm8: 命令找不到
sstm8: コマンドが見つかりません