A universal bash script for installing with apt-get and yum

Question

I'm trying to write a simple bash wrapper which abstracts yum and apt-get. Basically so we can do something like universal-install curl Here is what I have so far:

# universal-install
package=$1
apt=`command -v apt-get`
yum=`command -v yum`

if [ -n "$apt" ]; then
    apt-get update
    apt-get -y install $package
elif [ -n "$yum" ]; then
    yum -y install $package
else
    echo "Err: no path to apt-get or yum" >&2;
    exit 1;
fi

Are there any errors or improvements/optimizations that can be made?

Answer 1

Take a look at how pacapt detects the OS:

# Detect package type from /etc/issue
_found_arch() {
  local _ostype="$1"
  shift
  grep -qis "$*" /etc/issue && _OSTYPE="$_ostype"
}

# Detect package type
_OSTYPE_detect() {
  _found_arch PACMAN "Arch Linux" && return
  _found_arch DPKG   "Debian GNU/Linux" && return
  _found_arch DPKG   "Ubuntu" && return
  _found_arch YUM    "CentOS" && return
  _found_arch YUM    "Red Hat" && return
  _found_arch YUM    "Fedora" && return
  _found_arch ZYPPER "SUSE" && return

  [[ -z "$_OSTYPE" ]] || return

  # See also https://github.com/icy/pacapt/pull/22
  # Please not that $OSTYPE (which is `linux-gnu` on Linux system)
  # is not our $_OSTYPE. The choice is not very good because
  # a typo can just break the logic of the program.
  if [[ "$OSTYPE" != "darwin"* ]]; then
    _error "Can't detect OS type from /etc/issue. Running fallback method."
  fi
  [[ -x "/usr/bin/pacman" ]]           && _OSTYPE="PACMAN" && return
  [[ -x "/usr/bin/apt-get" ]]          && _OSTYPE="DPKG" && return
  [[ -x "/usr/bin/yum" ]]              && _OSTYPE="YUM" && return
  [[ -x "/opt/local/bin/port" ]]       && _OSTYPE="MACPORTS" && return
  command -v brew >/dev/null           && _OSTYPE="HOMEBREW" && return
  [[ -x "/usr/bin/emerge" ]]           && _OSTYPE="PORTAGE" && return
  [[ -x "/usr/bin/zypper" ]]           && _OSTYPE="ZYPPER" && return
  if [[ -z "$_OSTYPE" ]]; then
    _error "No supported package manager installed on system"
    _error "(supported: apt, homebrew, pacman, portage, yum)"
    exit 1
  fi
}

As you can see it first checks /etc/issue, then failing that the script looks for the associated executable file for each package manager.

But heck, why not just use pacapt, instead of rolling your own?

Answer 2

If you're going to do this, why require the user to tell the script which tool to use?

#!/bin/bash
# Find our package manager
if VERB="$( which apt-get )" 2> /dev/null; then
   echo "Debian-based"
elif VERB="$( which yum )" 2> /dev/null; then
   echo "Modern Red Hat-based"
elif VERB="$( which portage )" 2> /dev/null; then
   echo "Gentoo-based"
elif VERB="$( which pacman )" 2> /dev/null; then
   echo "Arch-based"
else
   echo "I have no idea what I'm doing." >&2
   exit 1
fi
if [[ 1 -ne $# ]]; then
   echo "Syntax: $0 PACKAGE"
   exit 1
fi
$VERB "$1"
exit $?

Slightly better would to to look at /etc/issue to see what your distribution is and behave accordingly.