sswap: 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/sswap - from package: secure-delete

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

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