psw: 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/psw - from package: wise2

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

On Debian possible default full paths are:

/usr/bin/psw - from package: wise

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

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