las2txt: 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/las2txt - from package: liblas-bin

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

Error in other languages:
las2txt: bevel nie gevind nie
las2txt: comandă negăsită
las2txt: comando não encontrado
las2txt: commande introuvable
las2txt: command not found
las2txt: käsku ei ole
las2txt: không tìm thấy lệnh
las2txt: komanda nerasta
las2txt: Kommando nicht gefunden.
las2txt: kommandot finns inte
las2txt: komut yok
las2txt: nie znaleziono polecenia
las2txt: níor aimsíodh an t-ordú
las2txt: no se encontró la orden
las2txt: no s'ha trobat l'ordre
las2txt: opdracht niet gevonden
las2txt: parancs nem található
las2txt: perintah tidak ditemukan
las2txt: príkaz nenájdený
las2txt: příkaz nenalezen
las2txt: команда не найдена
las2txt: командата не е открита
las2txt: 命令找不到
las2txt: コマンドが見つかりません