sml: 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/sml - from package: smlnj
/usr/lib/smlnj/bin/sml - from package: smlnj

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

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