Example code for OS detection

The following examples demonstrate how to programmatically detect the operating system and version using the /etc/os-release (or /usr/lib/os-release if /etc/os-release does not exist) file. These examples show how to distinguish between Amazon Linux and other distributions, as well as how to use the ID_LIKE field to determine distribution families.

The script below is implemented in several different programming languages, and each implementation will produce the same output.

Shell


#!/bin/bash

# Function to get a specific field from os-release file
get_os_release_field() {
    local field="$1"
    local os_release_file
    
    # Find the os-release file
    if [ -f /etc/os-release ]; then
        os_release_file='/etc/os-release'
    elif [ -f /usr/lib/os-release ]; then
        os_release_file='/usr/lib/os-release'
    else
        echo "Error: os-release file not found" >&2
        return 1
    fi
    
    # Source the file in a subshell and return the requested field.
    #
    # A subshell means that variables from os-release are only available
    # within the subshell, and the main script environment remains clean.
    (
        . "$os_release_file"
        eval "echo \"\$$field\""
    )
}

is_amazon_linux() {
    [ "$(get_os_release_field ID)" = "amzn" ]
}

is_fedora() {
    [ "$(get_os_release_field ID)" = "fedora" ]
}

is_ubuntu() {
    [ "$(get_os_release_field ID)" = "ubuntu" ]
}

is_debian() {
    [ "$(get_os_release_field ID)" = "debian" ]
}

# Function to check if this is like Fedora (includes Amazon Linux, CentOS, RHEL, etc.)
is_like_fedora() {
    local id="$(get_os_release_field ID)"
    local id_like="$(get_os_release_field ID_LIKE)"
    [ "$id" = "fedora" ] || [[ "$id_like" == *"fedora"* ]]
}

# Function to check if this is like Debian (includes Ubuntu and derivatives)
is_like_debian() {
    local id="$(get_os_release_field ID)"
    local id_like="$(get_os_release_field ID_LIKE)"
    [ "$id" = "debian" ] || [[ "$id_like" == *"debian"* ]]
}

# Get the main fields we'll use multiple times
ID="$(get_os_release_field ID)"
VERSION_ID="$(get_os_release_field VERSION_ID)"
PRETTY_NAME="$(get_os_release_field PRETTY_NAME)"
ID_LIKE="$(get_os_release_field ID_LIKE)"

echo "Operating System Detection Results:"
echo "=================================="
echo "Is Amazon Linux: $(is_amazon_linux && echo YES || echo NO)"
echo "Is Fedora: $(is_fedora && echo YES || echo NO)"
echo "Is Ubuntu: $(is_ubuntu && echo YES || echo NO)"
echo "Is Debian: $(is_debian && echo YES || echo NO)"
echo "Is like Fedora: $(is_like_fedora && echo YES || echo NO)"
echo "Is like Debian: $(is_like_debian && echo YES || echo NO)"
echo
echo "Detailed OS Information:"
echo "======================="
echo "ID: $ID"
echo "VERSION_ID: $VERSION_ID"
echo "PRETTY_NAME: $PRETTY_NAME"
[ -n "$ID_LIKE" ] && echo "ID_LIKE: $ID_LIKE"

# Amazon Linux specific information
if is_amazon_linux; then
    echo ""
    echo "Amazon Linux Version Details:"
    echo "============================="
    case "$VERSION_ID" in
        2018.03)
            echo "Amazon Linux AMI (version 1)"
            ;;
        2)
            echo "Amazon Linux 2"
            ;;
        2023)
            echo "Amazon Linux 2023"
            ;;
        *)
            echo "Unknown Amazon Linux version: $VERSION_ID"
            ;;
    esac
    
    # Check for Amazon Linux specific files
    [ -f /etc/image-id ] && echo "Amazon Linux image-id file present"
fi

Python 3.7-3.9


#!/usr/bin/env python3

import os
import sys

def parse_os_release():
    """Parse the os-release file and return a dictionary of key-value pairs."""
    os_release_data = {}
    
    # Try /etc/os-release first, then /usr/lib/os-release
    for path in ['/etc/os-release', '/usr/lib/os-release']:
        if os.path.exists(path):
            try:
                with open(path, 'r') as f:
                    for line in f:
                        line = line.strip()
                        if line and not line.startswith('#') and '=' in line:
                            key, value = line.split('=', 1)
                            # Remove quotes if present
                            value = value.strip('"\'')
                            os_release_data[key] = value
                return os_release_data
            except IOError:
                continue
    
    print("Error: os-release file not found")
    sys.exit(1)

def is_amazon_linux(os_data):
    """Check if this is Amazon Linux."""
    return os_data.get('ID') == 'amzn'

def is_fedora(os_data):
    """Check if this is Fedora."""
    return os_data.get('ID') == 'fedora'

def is_ubuntu(os_data):
    """Check if this is Ubuntu."""
    return os_data.get('ID') == 'ubuntu'

def is_debian(os_data):
    """Check if this is Debian."""
    return os_data.get('ID') == 'debian'

def is_like_fedora(os_data):
    """Check if this is like Fedora (includes Amazon Linux, CentOS, RHEL, etc.)."""
    if os_data.get('ID') == 'fedora':
        return True
    id_like = os_data.get('ID_LIKE', '')
    return 'fedora' in id_like

def is_like_debian(os_data):
    """Check if this is like Debian (includes Ubuntu and derivatives)."""
    if os_data.get('ID') == 'debian':
        return True
    id_like = os_data.get('ID_LIKE', '')
    return 'debian' in id_like

def main():
    # Parse os-release file
    os_data = parse_os_release()
    
    # Display results
    print("Operating System Detection Results:")
    print("==================================")
    print(f"Is Amazon Linux: {'YES' if is_amazon_linux(os_data) else 'NO'}")
    print(f"Is Fedora: {'YES' if is_fedora(os_data) else 'NO'}")
    print(f"Is Ubuntu: {'YES' if is_ubuntu(os_data) else 'NO'}")
    print(f"Is Debian: {'YES' if is_debian(os_data) else 'NO'}")
    print(f"Is like Fedora: {'YES' if is_like_fedora(os_data) else 'NO'}")
    print(f"Is like Debian: {'YES' if is_like_debian(os_data) else 'NO'}")
    
    # Additional information
    print()
    print("Detailed OS Information:")
    print("=======================")
    print(f"ID: {os_data.get('ID', '')}")
    print(f"VERSION_ID: {os_data.get('VERSION_ID', '')}")
    print(f"PRETTY_NAME: {os_data.get('PRETTY_NAME', '')}")
    if os_data.get('ID_LIKE'):
        print(f"ID_LIKE: {os_data.get('ID_LIKE')}")
    
    # Amazon Linux specific information
    if is_amazon_linux(os_data):
        print()
        print("Amazon Linux Version Details:")
        print("=============================")
        version_id = os_data.get('VERSION_ID', '')
        if version_id == '2018.03':
            print("Amazon Linux AMI (version 1)")
        elif version_id == '2':
            print("Amazon Linux 2")
        elif version_id == '2023':
            print("Amazon Linux 2023")
        else:
            print(f"Unknown Amazon Linux version: {version_id}")
        
        # Check for Amazon Linux specific files
        if os.path.exists('/etc/image-id'):
            print("Amazon Linux image-id file present")

if __name__ == '__main__':
    main()

Python 3.10+


#!/usr/bin/env python3

import os
import sys
import platform

def is_amazon_linux(os_data):
    """Check if this is Amazon Linux."""
    return os_data.get('ID') == 'amzn'

def is_fedora(os_data):
    """Check if this is Fedora."""
    return os_data.get('ID') == 'fedora'

def is_ubuntu(os_data):
    """Check if this is Ubuntu."""
    return os_data.get('ID') == 'ubuntu'

def is_debian(os_data):
    """Check if this is Debian."""
    return os_data.get('ID') == 'debian'

def is_like_fedora(os_data):
    """Check if this is like Fedora (includes Amazon Linux, CentOS, RHEL, etc.)."""
    if os_data.get('ID') == 'fedora':
        return True
    id_like = os_data.get('ID_LIKE', '')
    return 'fedora' in id_like

def is_like_debian(os_data):
    """Check if this is like Debian (includes Ubuntu and derivatives)."""
    if os_data.get('ID') == 'debian':
        return True
    id_like = os_data.get('ID_LIKE', '')
    return 'debian' in id_like

def main():
    # Parse os-release file using the standard library function (Python 3.10+)
    try:
        os_data = platform.freedesktop_os_release()
    except OSError:
        print("Error: os-release file not found")
        sys.exit(1)
    
    # Display results
    print("Operating System Detection Results:")
    print("==================================")
    print(f"Is Amazon Linux: {'YES' if is_amazon_linux(os_data) else 'NO'}")
    print(f"Is Fedora: {'YES' if is_fedora(os_data) else 'NO'}")
    print(f"Is Ubuntu: {'YES' if is_ubuntu(os_data) else 'NO'}")
    print(f"Is Debian: {'YES' if is_debian(os_data) else 'NO'}")
    print(f"Is like Fedora: {'YES' if is_like_fedora(os_data) else 'NO'}")
    print(f"Is like Debian: {'YES' if is_like_debian(os_data) else 'NO'}")
    
    # Additional information
    print()
    print("Detailed OS Information:")
    print("=======================")
    print(f"ID: {os_data.get('ID', '')}")
    print(f"VERSION_ID: {os_data.get('VERSION_ID', '')}")
    print(f"PRETTY_NAME: {os_data.get('PRETTY_NAME', '')}")
    if os_data.get('ID_LIKE'):
        print(f"ID_LIKE: {os_data.get('ID_LIKE')}")
    
    # Amazon Linux specific information
    if is_amazon_linux(os_data):
        print()
        print("Amazon Linux Version Details:")
        print("=============================")
        version_id = os_data.get('VERSION_ID', '')
        if version_id == '2018.03':
            print("Amazon Linux AMI (version 1)")
        elif version_id == '2':
            print("Amazon Linux 2")
        elif version_id == '2023':
            print("Amazon Linux 2023")
        else:
            print(f"Unknown Amazon Linux version: {version_id}")
        
        # Check for Amazon Linux specific files
        if os.path.exists('/etc/image-id'):
            print("Amazon Linux image-id file present")

if __name__ == '__main__':
    main()

Perl


#!/usr/bin/env perl

use strict;
use warnings;

# Function to parse the os-release file and return a hash of key-value pairs
sub parse_os_release {
    my %os_release_data;
    
    # Try /etc/os-release first, then /usr/lib/os-release
    my @paths = ('/etc/os-release', '/usr/lib/os-release');
    
    for my $path (@paths) {
        if (-f $path) {
            if (open(my $fh, '<', $path)) {
                while (my $line = <$fh>) {
                    chomp $line;
                    next if $line =~ /^\s*$/ || $line =~ /^\s*#/;
                    
                    if ($line =~ /^([^=]+)=(.*)$/) {
                        my ($key, $value) = ($1, $2);
                        # Remove quotes if present
                        $value =~ s/^["']|["']$//g;
                        $os_release_data{$key} = $value;
                    }
                }
                close($fh);
                return %os_release_data;
            }
        }
    }
    
    die "Error: os-release file not found\n";
}

# Function to check if this is Amazon Linux
sub is_amazon_linux {
    my %os_data = @_;
    return ($os_data{ID} // '') eq 'amzn';
}

# Function to check if this is Fedora
sub is_fedora {
    my %os_data = @_;
    return ($os_data{ID} // '') eq 'fedora';
}

# Function to check if this is Ubuntu
sub is_ubuntu {
    my %os_data = @_;
    return ($os_data{ID} // '') eq 'ubuntu';
}

# Function to check if this is Debian
sub is_debian {
    my %os_data = @_;
    return ($os_data{ID} // '') eq 'debian';
}

# Function to check if this is like Fedora (includes Amazon Linux, CentOS, RHEL, etc.)
sub is_like_fedora {
    my %os_data = @_;
    return 1 if ($os_data{ID} // '') eq 'fedora';
    my $id_like = $os_data{ID_LIKE} // '';
    return $id_like =~ /fedora/;
}

# Function to check if this is like Debian (includes Ubuntu and derivatives)
sub is_like_debian {
    my %os_data = @_;
    return 1 if ($os_data{ID} // '') eq 'debian';
    my $id_like = $os_data{ID_LIKE} // '';
    return $id_like =~ /debian/;
}

# Main execution
my %os_data = parse_os_release();

# Display results
print "Operating System Detection Results:\n";
print "==================================\n";
print "Is Amazon Linux: " . (is_amazon_linux(%os_data) ? "YES" : "NO") . "\n";
print "Is Fedora: " . (is_fedora(%os_data) ? "YES" : "NO") . "\n";
print "Is Ubuntu: " . (is_ubuntu(%os_data) ? "YES" : "NO") . "\n";
print "Is Debian: " . (is_debian(%os_data) ? "YES" : "NO") . "\n";
print "Is like Fedora: " . (is_like_fedora(%os_data) ? "YES" : "NO") . "\n";
print "Is like Debian: " . (is_like_debian(%os_data) ? "YES" : "NO") . "\n";
print "\n";

# Additional information
print "Detailed OS Information:\n";
print "=======================\n";
print "ID: " . ($os_data{ID} // '') . "\n";
print "VERSION_ID: " . ($os_data{VERSION_ID} // '') . "\n";
print "PRETTY_NAME: " . ($os_data{PRETTY_NAME} // '') . "\n";
print "ID_LIKE: " . ($os_data{ID_LIKE} // '') . "\n" if $os_data{ID_LIKE};

# Amazon Linux specific information
if (is_amazon_linux(%os_data)) {
    print "\n";
    print "Amazon Linux Version Details:\n";
    print "=============================\n";
    my $version_id = $os_data{VERSION_ID} // '';
    
    if ($version_id eq '2018.03') {
        print "Amazon Linux AMI (version 1)\n";
    } elsif ($version_id eq '2') {
        print "Amazon Linux 2\n";
    } elsif ($version_id eq '2023') {
        print "Amazon Linux 2023\n";
    } else {
        print "Unknown Amazon Linux version: $version_id\n";
    }
    
    # Check for Amazon Linux specific files
    if (-f '/etc/image-id') {
        print "Amazon Linux image-id file present\n";
    }
}

When run on different systems, the script will produce the following output:

AL2023

Operating System Detection Results:
==================================
Is Amazon Linux: YES
Is Fedora: NO
Is Ubuntu: NO
Is Debian: NO
Is like Fedora: YES
Is like Debian: NO

Detailed OS Information:
=======================
ID: amzn
VERSION_ID: 2023
PRETTY_NAME: Amazon Linux 2023.8.20250721
ID_LIKE: fedora

Amazon Linux Version Details:
=============================
Amazon Linux 2023
Amazon Linux image-id file present

AL2

Operating System Detection Results:
==================================
Is Amazon Linux: YES
Is Fedora: NO
Is Ubuntu: NO
Is Debian: NO
Is like Fedora: YES
Is like Debian: NO

Detailed OS Information:
=======================
ID: amzn
VERSION_ID: 2
PRETTY_NAME: Amazon Linux 2
ID_LIKE: centos rhel fedora

Amazon Linux Version Details:
=============================
Amazon Linux 2
Amazon Linux image-id file present

Amazon Linux AMI

Operating System Detection Results:
==================================
Is Amazon Linux: YES
Is Fedora: NO
Is Ubuntu: NO
Is Debian: NO
Is like Fedora: YES
Is like Debian: NO

Detailed OS Information:
=======================
ID: amzn
VERSION_ID: 2018.03
PRETTY_NAME: Amazon Linux AMI 2018.03
ID_LIKE: rhel fedora

Amazon Linux Version Details:
=============================
Amazon Linux AMI (version 1)
Amazon Linux image-id file present

Ubuntu

Operating System Detection Results:
==================================
Is Amazon Linux: NO
Is Fedora: NO
Is Ubuntu: YES
Is Debian: NO
Is like Fedora: NO
Is like Debian: YES

Detailed OS Information:
=======================
ID: ubuntu
VERSION_ID: 24.04
PRETTY_NAME: Ubuntu 24.04.2 LTS
ID_LIKE: debian

Debian

Operating System Detection Results:
==================================
Is Amazon Linux: NO
Is Fedora: NO
Is Ubuntu: NO
Is Debian: YES
Is like Fedora: NO
Is like Debian: YES

Detailed OS Information:
=======================
ID: debian
VERSION_ID: 12
PRETTY_NAME: Debian GNU/Linux 12 (bookworm)

Fedora

Operating System Detection Results:
==================================
Is Amazon Linux: NO
Is Fedora: YES
Is Ubuntu: NO
Is Debian: NO
Is like Fedora: YES
Is like Debian: NO

Detailed OS Information:
=======================
ID: fedora
VERSION_ID: 42
PRETTY_NAME: Fedora Linux 42 (Container Image)

Warning Javascript is disabled or is unavailable in your browser.

To use the Amazon Web Services Documentation, Javascript must be enabled. Please refer to your browser's Help pages for instructions.

Document Conventions

Amazon Linux Specific

AWS integration in AL2