Find out which package I have to install on a Linux system

I made a bash script to install a software package on a Linux system. There are 4 packages I can use to install the software:

1. x86.deb
2. x86.rpm
3. x86_64.deb
4. x86_64.rpm

I know when to install which package on which Linux server manually, but I would like to find out "automatically" (in my bash script) which one I have to install.

Is there any command to find out? I already know there is a way to find out the architecture (32-bit or 64-bit) via the "arch" command, but I do not know how to find out which package I need.

uname -m or arch gives you the architecture (x86_64 or similar).

You can probably figure out whether your system is based on RPM or DEB (e.g. Ubuntu is DEB-based) by asking both variants which package installed /bin/ls:

dpkg -S /bin/ls

will print

coreutils: /bin/ls

on a DEB-based system.

rpm -q -f /bin/ls

will print

coreutils-5.97-23.el5_6.4

on an RPM-based system (with probably different version numbers).

On the "wrong" system each of these will give an error message instead.

if dpkg -S /bin/ls >/dev/null 2>&1
then
  case "$(arch)" in
    x86_64)
      sudo dpkg -i x86_64.deb;;
    i386)
      sudo dpkg -i x86.deb;;
    *)
      echo "Don't know how to handle $(arch)"
      exit 1
      ;;
  esac
elif rpm -q -f /bin/ls >/dev/null 2>&1
then
  case "$(arch)" in
    x86_64)
      sudo rpm -i x86_64.rpm;;
    i386)
      sudo rpm -i x86.rpm;;
    *)
      echo "Don't know how to handle $(arch)"
      exit 1
      ;;
  esac
else
  echo "Don't know this package system (neither RPM nor DEB)."
  exit 1
fi

Of course, all this only makes sense in case you know what to do then, i.e. if you know which package is to be installed on which package system with which architecture.