rebar: 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/bin/rebar - from package: rebar

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