banana: 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/banana - from package: emboss

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

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