posh.dbg: 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/lib/debug/bin/posh.dbg - from package: posh-dbg

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

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