httping: 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/httping - from package: httping

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

On Debian possible default full paths are:

/usr/bin/httping - from package: httping

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

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