mruby-strip: 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/mruby-strip - from package: mruby

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

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