hardlink: 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/sbin/hardlink - from package: hardlink

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

On Debian possible default full paths are:

/usr/bin/hardlink - from package: hardlink

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

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