meshlab: 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/meshlab - from package: meshlab

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

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