lsb_release: 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/lsb_release - from package: redhat-lsb-core

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

On Debian possible default full paths are:

/usr/bin/lsb_release - from package: lsb-release

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

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