m2sh: 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/m2sh - from package: mongrel2-core

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

Error in other languages:
m2sh: bevel nie gevind nie
m2sh: comandă negăsită
m2sh: comando não encontrado
m2sh: commande introuvable
m2sh: command not found
m2sh: käsku ei ole
m2sh: không tìm thấy lệnh
m2sh: komanda nerasta
m2sh: Kommando nicht gefunden.
m2sh: kommandot finns inte
m2sh: komut yok
m2sh: nie znaleziono polecenia
m2sh: níor aimsíodh an t-ordú
m2sh: no se encontró la orden
m2sh: no s'ha trobat l'ordre
m2sh: opdracht niet gevonden
m2sh: parancs nem található
m2sh: perintah tidak ditemukan
m2sh: príkaz nenájdený
m2sh: příkaz nenalezen
m2sh: команда не найдена
m2sh: командата не е открита
m2sh: 命令找不到
m2sh: コマンドが見つかりません