unicode: 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/lib/plan9/bin/unicode - from package: 9base
/usr/bin/unicode - from package: unicode

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

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