pcl_add_gaussian_noise: 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 Debian possible default full paths are:

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

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

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