pcl_ply2raw: command not found

Have You tried accessing the binary with the full path?

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/pcl_ply2raw - from package: pcl-tools

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

On Debian possible default full paths are:

/usr/bin/pcl_ply2raw - from package: pcl-tools

You may install the required package with command apt-get install {package}
Error in other languages:
pcl_ply2raw: bevel nie gevind nie
pcl_ply2raw: comandă negăsită
pcl_ply2raw: comando não encontrado
pcl_ply2raw: commande introuvable
pcl_ply2raw: command not found
pcl_ply2raw: käsku ei ole
pcl_ply2raw: không tìm thấy lệnh
pcl_ply2raw: komanda nerasta
pcl_ply2raw: Kommando nicht gefunden.
pcl_ply2raw: kommandot finns inte
pcl_ply2raw: komut yok
pcl_ply2raw: nie znaleziono polecenia
pcl_ply2raw: níor aimsíodh an t-ordú
pcl_ply2raw: no se encontró la orden
pcl_ply2raw: no s'ha trobat l'ordre
pcl_ply2raw: opdracht niet gevonden
pcl_ply2raw: parancs nem található
pcl_ply2raw: perintah tidak ditemukan
pcl_ply2raw: príkaz nenájdený
pcl_ply2raw: příkaz nenalezen
pcl_ply2raw: команда не найдена
pcl_ply2raw: командата не е открита
pcl_ply2raw: 命令找不到
pcl_ply2raw: コマンドが見つかりません