lscpu: 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/lscpu - from package: util-linux-ng

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

On Debian possible default full paths are:

/usr/bin/lscpu - from package: util-linux

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

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