tidy-proxy: 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/tidy-proxy - from package: tidy-proxy

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

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