checksecurity: 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 Debian possible default full paths are:

/usr/sbin/checksecurity - from package: checksecurity

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

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