scilab-cli: 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/scilab-cli - from package: scilab-cli

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

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