gistfile1.txt

#!/bin/bash
 
# Try and get debian operating system
# id, codename, and release

TYPE=$(echo "$1" | tr '[A-Z]' '[a-z]')
OS=$(uname)
ID="unknown"
CODENAME="unknown"
RELEASE="unknown"

if [ "$OS" == "Linux" ]; then
    # detect centos
    grep "centos" /etc/issue -i -q
    if [ $? = '0' ]; then
        ID="centos"
        RELEASE=$(cat /etc/redhat-release | grep -o 'release [0-9]' | cut -d " " -f2)
    # could be debian or ubuntu
    elif [ $(which lsb_release) ]; then
        ID=$(lsb_release -i | cut -f2)
        CODENAME=$(lsb_release -c | cut -f2)
        RELEASE=$(lsb_release -r | cut -f2)
    elif [ -f "/etc/lsb-release" ]; then
        ID=$(cat /etc/lsb-release | grep DISTRIB_ID | cut -d "=" -f2)
        CODENAME=$(cat /etc/lsb-release | grep DISTRIB_CODENAME | cut -d "=" -f2)
        RELEASE=$(cat /etc/lsb-release | grep DISTRIB_RELEASE | cut -d "=" -f2)
    elif [ -f "/etc/issue" ]; then
        ID=$(head -1 /etc/issue | cut -d " " -f1)
        if [ -f "/etc/debian_version" ]; then
          RELEASE=$(</etc/debian_version)
        else
          RELEASE=$(head -1 /etc/issue | cut -d " " -f2)
        fi
    fi
fi

declare -A info

info[id]=$(echo "$ID" | tr '[A-Z]' '[a-z]')
info[codename]=$(echo "$CODENAME" | tr '[A-Z]' '[a-z]')
info[release]=$(echo "$RELEASE" | tr '[A-Z]' '[a-z]')

if [ "$TYPE" ] ; then 
    echo "${info[$TYPE]}"
else 
    echo -e "ID\t${info[id]}"
    echo -e "CODENAME\t${info[codename]}"
    echo -e "RELEASE\t${info[release]}"
fi