repl: 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/mu-mh/repl - from package: mailutils-mh
/usr/bin/mh/repl - from package: nmh

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

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