science-engineering: 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/science-engineering - from package: science-engineering

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

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