osh: 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/osh - from package: omake

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

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