cinnamon: 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/cinnamon - from package: cinnamon

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

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