lz4: 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/lz4 - from package: lz4

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

On Debian possible default full paths are:

/usr/bin/lz4 - from package: liblz4-tool

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

Error in other languages:
lz4: bevel nie gevind nie
lz4: comandă negăsită
lz4: comando não encontrado
lz4: commande introuvable
lz4: command not found
lz4: käsku ei ole
lz4: không tìm thấy lệnh
lz4: komanda nerasta
lz4: Kommando nicht gefunden.
lz4: kommandot finns inte
lz4: komut yok
lz4: nie znaleziono polecenia
lz4: níor aimsíodh an t-ordú
lz4: no se encontró la orden
lz4: no s'ha trobat l'ordre
lz4: opdracht niet gevonden
lz4: parancs nem található
lz4: perintah tidak ditemukan
lz4: príkaz nenájdený
lz4: příkaz nenalezen
lz4: команда не найдена
lz4: командата не е открита
lz4: 命令找不到
lz4: コマンドが見つかりません