tilda: 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/tilda - from package: tilda

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

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