hwloc-ls: 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/hwloc-ls - from package: hwloc

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

On Debian possible default full paths are:

/usr/bin/hwloc-ls - from package: hwloc-nox
/usr/bin/hwloc-ls - from package: hwloc

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

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