prettyplot: 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/prettyplot - from package: emboss

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

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