outguess-histogram: 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/outguess-histogram - from package: outguess

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

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