rant: 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/rant - from package: rant

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

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