rmidish: 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/rmidish - from package: midish

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

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