unagi: command not found

Have You tried accessing the binary with the full path?

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/debug/usr/bin/unagi - from package: unagi-dbg
/usr/bin/unagi - from package: unagi

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