How to check if running in Cygwin Mac or Linux

Question

I have a shell script that is used both on Windows Cygwin and Mac and Linux  It needs slightly  different variables for each versions   How can a shell bash script detect whether it is running in Cygwin  on a Mac or in Linux

User · Answer

Bash sets the shell variable OSTYPE  From man bash      Automatically set to a string that describes the operating system on   which bash is executing    This has a tiny advantage over uname in that it doesn t require launching a new process  so will be quicker to execute   However  I m unable to find an authoritative list of expected values  For me on Ubuntu 14 04 it is set to  linux-gnu   I ve scraped the web for some other values  Hence   case   OSTYPE  in   linux     echo  Linux   WSL       darwin    echo  Mac OS        win       echo  Windows       msys      echo  MSYS   MinGW   Git Bash       cygwin    echo  Cygwin       bsd       echo  BSD       solaris   echo  Solaris                 echo  unknown   OSTYPE     esac   The asterisks are important in some instances - for example OSX appends an OS version number after the  darwin   The  win  value is actually  win32   I m told - maybe there is a  win64    Perhaps we could work together to populate a table of verified values here    Linux Ubuntu  incl  WSL   linux-gnu Cygwin 64-bit  cygwin Msys MINGW  Git Bash for Windows   msys    Please append your value if it differs from existing entries

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Here is the bash script I used to detect three different OS type  GNU Linux  Mac OS X  Windows NT   Pay attention   In your bash script  use    usr bin env bash instead of    bin sh to prevent the problem caused by  bin sh linked to different default shell in different platforms  or there will be error like unexpected operator  that s what happened on my computer  Ubuntu 64 bits 12 04   Mac OS X 10 6 8  Snow Leopard  do not have expr program unless you install it  so I just use uname    Design   Use uname to get the system information  -s parameter   Use expr and substr to deal with the string  Use if elif fi to do the matching job  You can add more system support if you want  just follow the uname -s specification    Implementation     usr bin env bash  if      uname       Darwin     then       Do something under Mac OS X platform         elif      expr substr   uname -s  1 5       Linux     then       Do something under GNU Linux platform elif      expr substr   uname -s  1 10       MINGW32 NT     then       Do something under 32 bits Windows NT platform elif      expr substr   uname -s  1 10       MINGW64 NT     then       Do something under 64 bits Windows NT platform fi   Testing   Linux  Ubuntu 12 04 LTS  Kernel 3 2 0  tested OK  OS X  10 6 8 Snow Leopard  tested OK  Windows  Windows 7 64 bit  tested OK    What I learned   Check for both opening and closing quotes  Check for missing parentheses and braces      References    1  uname - wikipedia  2  shell script syntax error  unexpected end of file  3  Detect the OS from a Bash script  4  BASH Programming Introduction HOW-TO

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Usually  uname with its various options will tell you what environment you re running in   pax gt  uname -a CYGWIN NT-5 1 IBM-L3F3936 1 5 25 0 156 4 2  2008-06-12 19 34 i686 Cygwin  pax gt  uname -s CYGWIN NT-5 1   And  according to the very helpful schot  in the comments   uname -s gives Darwin for OSX and Linux for Linux  while my Cygwin gives CYGWIN NT-5 1  But you may have to experiment with all sorts of different versions   So the bash code to do such a check would be along the lines of   unameOut    uname -s   case    unameOut   in     Linux       machine Linux       Darwin      machine Mac       CYGWIN      machine Cygwin       MINGW       machine MinGw                   machine  UNKNOWN   unameOut   esac echo   machine      Note that I m assuming here that you re actually running within CygWin  the bash shell of it  so paths should already be correctly set up  As one commenter notes  you can run the bash program  passing the script  from cmd itself and this may result in the paths not being set up as needed   If you are doing that  it s your responsibility to ensure the correct executables  i e   the CygWin ones  are being called  possibly by modifying the path beforehand or fully specifying the executable locations  e g    c cygwin bin uname

User · Answer

To build upon Albert s answer  I like to use  COMSPEC for detecting Windows      bin bash  if      uname       Darwin    then  echo Do something under Mac OS X platform elif      expr substr   uname -s  1 5       Linux    then   echo Do something under Linux platform elif   -n   COMSPEC  -a -x   COMSPEC    then    echo  0  this script does not support Windows      fi   This avoids parsing variants of Windows names for  OS  and parsing variants of uname like MINGW  Cygwin  etc   Background   COMSPEC  is a Windows environmental variable specifying the full path to the command processor  aka the Windows shell    The value of this variable is typically  SystemRoot  system32 cmd exe  which typically evaluates to C  Windows system32 cmd exe

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http   en wikipedia org wiki Uname  All the info you ll ever need  Google is your friend   Use uname -s to query the system name    Mac  Darwin Cygwin  CYGWIN     Linux  various  LINUX for most

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I guess the uname answer is unbeatable  mainly in terms of cleanliness   Although it takes a ridiculous time to execute  I found that testing for specific files presence also gives me good and quicker results  since I m not invoking an executable   So     -f  usr bin cygwin1 dll    amp  amp  echo Yep  Cygwin running  just uses a quick Bash file presence check  As I m on Windows right now  I can t tell you any specific files for Linuxes and Mac OS X from my head  but I m pretty sure they do exist   -

User · Answer

Ok  here is my way   osis         local n 0     if      1     -n      then n 1 shift  fi        echo  OS grep  1 -i  gt  dev null     uname -s  grep -i   1   gt  dev null      return      n             e g   osis Darwin  amp  amp        log debug Detect mac osx   osis Linux  amp  amp        log debug Detect linux   osis -n Cygwin  amp  amp        log debug Not Cygwin     I use this in my dotfiles

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Use uname -s  --kernel-name  because uname -o  --operating-system  is not supported on some Operating Systems such as Mac OS and Solaris  You may also use just uname without any argument since the default argument is -s  --kernel-name   The below snippet does not require bash  i e  does not require    bin bash     bin sh  case  quot   uname -s  quot  in     Darwin       echo  Mac OS X              Linux       echo  Linux              CYGWIN  MINGW32  MSYS  MINGW        echo  MS Windows                Add here more strings to compare      See correspondence table at the bottom of this answer             echo  Other OS           esac  The below Makefile is inspired from Git project  config mak uname   ifdef MSVC       Avoid the MingW Cygwin sections     uname S    Windows else                            If uname not available   gt   not       uname S      shell sh -c  uname -s 2 gt  dev null    echo not   endif    Avoid nesting  quot if    else if    else    endif endif quot    because maintenance of matching if else endif is a pain  ifeq    uname S  Windows      CC    cl  endif ifeq    uname S  OSF1      CFLAGS    -D OSF SOURCE endif ifeq    uname S  Linux      CFLAGS    -DNDEBUG endif ifeq    uname S  GNU kFreeBSD      CFLAGS    -D BSD ALLOC endif ifeq    uname S  UnixWare      CFLAGS    -Wextra endif      See also this complete answer about uname -s and Makefile  The correspondence table in the bottom of this answer is from Wikipedia article about uname  Please contribute to keep it up-to-date  edit the answer or post a comment   You may also update the Wikipedia article and post a comment to notify me about your contribution  -   Operating System            uname -s                 Mac OS X                    Darwin                   Cygwin 32-bit  Win-XP       CYGWIN NT-5 1            Cygwin 32-bit  Win-7 32-bit CYGWIN NT-6 1            Cygwin 32-bit  Win-7 64-bit CYGWIN NT-6 1-WOW64      Cygwin 64-bit  Win-7 64-bit CYGWIN NT-6 1            MinGW  Windows 7 32-bit     MINGW32 NT-6 1           MinGW  Windows 10 64-bit    MINGW64 NT-10 0          Interix  Services for UNIX  Interix                  MSYS                        MSYS NT-6 1              MSYS2                       MSYS NT-10 0-17763       Windows Subsystem for Linux Linux                    Android                     Linux                    coreutils                   Linux                    CentOS                      Linux                    Fedora                      Linux                    Gentoo                      Linux                    Red Hat Linux               Linux                    Linux Mint                  Linux                    openSUSE                    Linux                    Ubuntu                      Linux                    Unity Linux                 Linux                    Manjaro Linux               Linux                    OpenWRT r40420              Linux                    Debian  Linux               Linux                    Debian  GNU Hurd            GNU                      Debian  kFreeBSD            GNU kFreeBSD             FreeBSD                     FreeBSD                  NetBSD                      NetBSD                   OpenBSD                     OpenBSD                  DragonFlyBSD                DragonFly                Haiku                       Haiku                    NonStop                     NONSTOP KERNEL           QNX                         QNX                      ReliantUNIX                 ReliantUNIX-Y            SINIX                       SINIX-Y                  Tru64                       OSF1                     Ultrix                      ULTRIX                   IRIX 32 bits                IRIX                     IRIX 64 bits                IRIX64                   MINIX                       Minix                    Solaris                     SunOS                    UWIN  64-bit Windows 7      UWIN-W7                  SYS UNIX SH on OpenVMS      IS WB                    z OS USS                    OS 390                   Cray                        sn5176                    SCO  OpenServer            SCO SV                    SCO  System V              SCO SV                    SCO  UnixWare              UnixWare                 IBM AIX                     AIX                      IBM i with QSH              OS400                    HP-UX                       HP-UX

User · Answer

Windows Subsystem for Linux did not exist when this question was asked  It gave these results in my test   uname -s - gt  Linux uname -o - gt  GNU Linux uname -r - gt  4 4 0-17763-Microsoft   This means that you need uname -r to distinguish it from  native Linux

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Use only this from command line works very fine  thanks to Justin      bin bash                                                                 Bash script to find which OS                                                               OS  uname  echo   OS    source

User · Answer

This script fragment emits Cygwin rulez under bash cygwin if      uname -s     CYGWIN     then     echo Cygwin rulez else      echo Unix is king fi   If the 6 first chars of uname -s command is  CYGWIN   a cygwin system is assumed

[bash] How to check if running in Cygwin, Mac or Linux?

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