treeline: 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/treeline - from package: treeline

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

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