htpurge: 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 CentOS possible default full paths are:

/usr/bin/htpurge - from package: htdig

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/htpurge - from package: htdig

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

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