swappo: 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 CentOS possible default full paths are:

/usr/bin/swappo - from package: kdesdk-utils

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/swappo - from package: poxml

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

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