How to detect the OS from a Bash script?

Question

I would like to keep my .bashrc and .bash_login files in version control so that I can use them between all the computers I use. The problem is I have some OS specific aliases so I was looking for a way to determine if the script is running on Mac OS X, Linux or Cygwin.

What is the proper way to detect the operating system in a Bash script?

Answer 1

Below it's an approach to detect Debian and RedHat based Linux OS making use of the /etc/lsb-release and /etc/os-release (depending on the Linux flavor you're using) and take a simple action based on it.

#!/bin/bash
set -e

YUM_PACKAGE_NAME="python python-devl python-pip openssl-devel"
DEB_PACKAGE_NAME="python2.7 python-dev python-pip libssl-dev"

 if cat /etc/*release | grep ^NAME | grep CentOS; then
    echo "==============================================="
    echo "Installing packages $YUM_PACKAGE_NAME on CentOS"
    echo "==============================================="
    yum install -y $YUM_PACKAGE_NAME
 elif cat /etc/*release | grep ^NAME | grep Red; then
    echo "==============================================="
    echo "Installing packages $YUM_PACKAGE_NAME on RedHat"
    echo "==============================================="
    yum install -y $YUM_PACKAGE_NAME
 elif cat /etc/*release | grep ^NAME | grep Fedora; then
    echo "================================================"
    echo "Installing packages $YUM_PACKAGE_NAME on Fedorea"
    echo "================================================"
    yum install -y $YUM_PACKAGE_NAME
 elif cat /etc/*release | grep ^NAME | grep Ubuntu; then
    echo "==============================================="
    echo "Installing packages $DEB_PACKAGE_NAME on Ubuntu"
    echo "==============================================="
    apt-get update
    apt-get install -y $DEB_PACKAGE_NAME
 elif cat /etc/*release | grep ^NAME | grep Debian ; then
    echo "==============================================="
    echo "Installing packages $DEB_PACKAGE_NAME on Debian"
    echo "==============================================="
    apt-get update
    apt-get install -y $DEB_PACKAGE_NAME
 elif cat /etc/*release | grep ^NAME | grep Mint ; then
    echo "============================================="
    echo "Installing packages $DEB_PACKAGE_NAME on Mint"
    echo "============================================="
    apt-get update
    apt-get install -y $DEB_PACKAGE_NAME
 elif cat /etc/*release | grep ^NAME | grep Knoppix ; then
    echo "================================================="
    echo "Installing packages $DEB_PACKAGE_NAME on Kanoppix"
    echo "================================================="
    apt-get update
    apt-get install -y $DEB_PACKAGE_NAME
 else
    echo "OS NOT DETECTED, couldn't install package $PACKAGE"
    exit 1;
 fi

exit 0

Output example for Ubuntu Linux:

delivery@delivery-E5450$ sudo sh detect_os.sh
[sudo] password for delivery: 
NAME="Ubuntu"
===============================================
Installing packages python2.7 python-dev python-pip libssl-dev on Ubuntu
===============================================
Ign http://dl.google.com stable InRelease
Get:1 http://dl.google.com stable Release.gpg [916 B]                          
Get:2 http://dl.google.com stable Release [1.189 B] 
...            

Answer 2

I tend to keep my .bashrc and .bash_alias on a file share that all platforms can access. This is how I conquer the problem in my .bash_alias:

if [[ -f (name of share)/.bash_alias_$(uname) ]]; then
    . (name of share)/.bash_alias_$(uname)
fi

And I have for example a .bash_alias_Linux with:

alias ls='ls --color=auto'

This way I keep platform specific and portable code separate, you can do the same for .bashrc

Answer 3

I would suggest avoiding some of these answers. Don't forget that you can choose other forms of string comparison, which would clear up most of the variations, or ugly code offered.

One such solution would be a simple check, such as:

if [[ "$OSTYPE" =~ ^darwin ]]; then

Which has the added benefit of matching any version of Darwin, despite it's version suffix. This also works for any variations of Linux one may expect.

You can see some additional examples within my dotfiles here