freemat: 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/freemat - from package: freemat

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

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