lxc-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/lxc-ls - from package: lxc

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

On Debian possible default full paths are:

/usr/bin/lxc-ls - from package: lxc

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

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