check-selinux-installation: 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/check-selinux-installation - from package: selinux-basics

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

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