pia: 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/pia - from package: xawtv

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

On Debian possible default full paths are:

/usr/bin/pia - from package: pia

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

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