lsar: command not found

Have You tried accessing the binary with the full path?

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 Debian possible default full paths are:

/usr/bin/lsar - from package: unar

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