Identify Linux OS

detect linux OS

#!/bin/bash

detect_os (){
    # Check the OS version
    if [ -f /etc/os-release ]; then
        source /etc/os-release
    else
        # Most likely a Centos5/6 box
        if [ -f /etc/redhat-release ]; then
            if grep -iq centos "/etc/redhat-release"; then
                ID="centos"
            fi
        fi
    fi
}

#####
CentOS 7
cat /etc/os-release

NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"

source

detect_os ()
{
  if [[ ( -z "${os}" ) && ( -z "${dist}" ) ]]; then
    if [ -e /etc/os-release ]; then
      . /etc/os-release
      os=${ID}
      if [ "${os}" = "poky" ]; then
        dist=`echo ${VERSION_ID}`
      elif [ "${os}" = "sles" ]; then
        dist=`echo ${VERSION_ID}`
      elif [ "${os}" = "opensuse" ]; then
        dist=`echo ${VERSION_ID}`
      elif [ "${os}" = "opensuse-leap" ]; then
        os=opensuse
        dist=`echo ${VERSION_ID}`
      else
        dist=`echo ${VERSION_ID} | awk -F '.' '{ print $1 }'`
      fi

    elif [ `which lsb_release 2>/dev/null` ]; then
      # get major version (e.g. '5' or '6')
      dist=`lsb_release -r | cut -f2 | awk -F '.' '{ print $1 }'`

      # get os (e.g. 'centos', 'redhatenterpriseserver', etc)
      os=`lsb_release -i | cut -f2 | awk '{ print tolower($1) }'`

    elif [ -e /etc/oracle-release ]; then
      dist=`cut -f5 --delimiter=' ' /etc/oracle-release | awk -F '.' '{ print $1 }'`
      os='ol'

    elif [ -e /etc/fedora-release ]; then
      dist=`cut -f3 --delimiter=' ' /etc/fedora-release`
      os='fedora'

    elif [ -e /etc/redhat-release ]; then
      os_hint=`cat /etc/redhat-release  | awk '{ print tolower($1) }'`
      if [ "${os_hint}" = "centos" ]; then
        dist=`cat /etc/redhat-release | awk '{ print $3 }' | awk -F '.' '{ print $1 }'`
        os='centos'
      elif [ "${os_hint}" = "scientific" ]; then
        dist=`cat /etc/redhat-release | awk '{ print $4 }' | awk -F '.' '{ print $1 }'`
        os='scientific'
      else
        dist=`cat /etc/redhat-release  | awk '{ print tolower($7) }' | cut -f1 --delimiter='.'`
        os='redhatenterpriseserver'
      fi

    else
      aws=`grep -q Amazon /etc/issue`
      if [ "$?" = "0" ]; then
        dist='6'
        os='aws'
      else
        unknown_os
      fi
    fi
  fi

  if [[ ( -z "${os}" ) || ( -z "${dist}" ) ]]; then
    unknown_os
  fi

  # remove whitespace from OS and dist name
  os="${os// /}"
  dist="${dist// /}"

  echo "Detected operating system as ${os}/${dist}."
}