I have Perl on Mac, Windows and Ubuntu. How can I tell from within the script which one is which? Thanks in advance.
Edit: I was asked what I am doing. It is a script, part of our cross-platform build system. The script recurses directories and figures out what files to build. Some files are platform-specific, and thus, on Linux I don't want to build the files ending with _win.cpp, etc.
Examine the $^O variable which will contain the name of the operating system:
print "$^O\n";
Which prints linux on Linux and MSWin32 on Windows.
You can also refer to this variable by the name $OSNAME if you use the English module:
use English qw' -no_match_vars ';
print "$OSNAME\n";
According to perlport, $^O will be darwin on Mac OS X.
You can also use the Config core module, which can provide the same information (and a lot more):
use Config;
print "$Config{osname}\n";
print "$Config{archname}\n";
Which on my Ubuntu machine prints:
linux
i486-linux-gnu-thread-multi
Note that this information is based on the system that Perl was built, which is not necessarily the system Perl is currently running on (the same is true for $^O and $OSNAME); the OS won't likely be different but some information, like the architecture name, may very well be.
If you need more specific information on Windows this may help.
my $osname = $^O;
if( $osname eq 'MSWin32' ){{
eval { require Win32; } or last;
$osname = Win32::GetOSName();
# work around for historical reasons
$osname = 'WinXP' if $osname =~ /^WinXP/;
}}
Derived from sysinfo.t, which I wrote the original version.
If you need more detailed information:
my ( $osvername, $major, $minor, $id ) = Win32::GetOSVersion();
Sys::Info::OS looks like a relatively clean potential solution, but currently doesn't seem to support Mac. It shouldn't be too much work to add that though.
Look inside the source for File::Spec to see how it loads the right delegate based on the operating system. :)
File::Spec has a separate Perl module file for each OS. File::Spec::Win32, File::Spec::OS2, etc...
It checks the operating system and will load the appropriate .pm file at runtime based on OS.
# From the source code of File::Spec
my %module = (
MSWin32 => 'Win32',
os2 => 'OS2',
VMS => 'VMS',
NetWare => 'Win32', # Yes, File::Spec::Win32 works on NetWare.
symbian => 'Win32', # Yes, File::Spec::Win32 works on symbian.
dos => 'OS2', # Yes, File::Spec::OS2 works on DJGPP.
cygwin => 'Cygwin',
amigaos => 'AmigaOS');
my $module = $module{$^O} || 'Unix';
require "File/Spec/$module.pm";
our @ISA = ("File::Spec::$module");
Here's a quick reference on how to find the OS the local machine is running from Perl.
The $^O variable ($OSTYPE if you use English) contains the operating system that your perl binary was built for.
#Assign the $home_directory variable the path of the user's home directory
my $home_directory = ($^O eq /Win/) ? $ENV{HOMEPATH} : $ENV{HOME};
#Then you can read/write to files in the home directory
open(FILE, ">$home_directory/my_tmp_file");
print FILE "This is a test\n";
close FILE;
#And/or read the contents of the file
open(FILE, "<$home_directory/my_tmp_file");
while (<FILE>){
print $_;
}
close FILE;
For a generic mapping in a pre-packaged perl module, check out Perl::OSType.
It's used by Module::Build.
