snefru: command not found

Have You tried accessing the binary with the full path?

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/tiger/bin/snefru - from package: tiger

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