bless: 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/bless - from package: bless

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

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