Check what linux package manager is used [BASH]

checkpkgman.sh

function apt {
    which apt > /dev/null 2>&1
    if [ "$?" -eq "0" ]; then
        apt install THEPACKAGES
}
function pacman {
    which pacman > /dev/null 2>&1
    if [ "$?" -eq "0" ]; then
        pacman -S THEPACKAGES  
}
function zypper {
    which zypper > /dev/null 2>&1
    if [ "$?" -eq "0" ]; then
        zypper install THEPACKAGES
function dnf {
    which dnf > /dev/null 2>&1
    if [ "$?" -eq "0" ]; then
        dnf install THEPACKAGES
}
function yum {
    which yum > /dev/null 2>&1
    if [ "$?" -eq "0" ]; then
    yum install THEPACKAGES
}