psmandup: 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/psmandup - from package: a2ps

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

On Debian possible default full paths are:

/usr/bin/psmandup - from package: a2ps

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

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