las2las: 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 Debian possible default full paths are:

/usr/bin/las2las - from package: liblas-bin

You may install the required package with command apt-get install {package}
Error in other languages:
las2las: bevel nie gevind nie
las2las: comandă negăsită
las2las: comando não encontrado
las2las: commande introuvable
las2las: command not found
las2las: käsku ei ole
las2las: không tìm thấy lệnh
las2las: komanda nerasta
las2las: Kommando nicht gefunden.
las2las: kommandot finns inte
las2las: komut yok
las2las: nie znaleziono polecenia
las2las: níor aimsíodh an t-ordú
las2las: no se encontró la orden
las2las: no s'ha trobat l'ordre
las2las: opdracht niet gevonden
las2las: parancs nem található
las2las: perintah tidak ditemukan
las2las: príkaz nenájdený
las2las: příkaz nenalezen
las2las: команда не найдена
las2las: командата не е открита
las2las: 命令找不到
las2las: コマンドが見つかりません