How To Process System Exit Codes Using Perl Eval

Author: erics, March 9th, 2021

The trick to using eval to catch shell execution is to return twice, once inside the eval and once outside:

sub isMaintenance {
    my $return = eval {
        my $err=system("check_policy.sh | grep 'Policy is MAINTENANCE' >/dev/null 2>/dev/null");
        &debug("perl error code: $err");
        $err=$err / 256;
        &debug("system error code: $err");
        if ($err != 0) {
                # Not Maintenance
                if ($verbose) { warn "policy is NOT MAINTENANCE\n"; }
                return 0;
        } else { return 1; }
    };  
    return $return;
}

sub isMaintenance {

my $return = eval {

my $err=system("check_policy.sh | grep 'Policy is MAINTENANCE' >/dev/null 2>/dev/null");

&debug("perl error code: $err");

$err=$err / 256;

&debug("system error code: $err");

if ($err != 0) {

# Not Maintenance

if ($verbose) { warn "policy is NOT MAINTENANCE\n"; }

return 0;

} else { return 1; }

};

return $return;

}

Neat!

Categories: How-To's, Technology Tags: Code, eval, Exit, Exit Code, howto, perl, Return, System | No comments

How To Properly Specify Command and Arguments to Exec in Perl

Author: erics, December 11th, 2019

When using Perl’s exec() call, the best way to invoke it is as follows:

exec("$dir/myprog.sh",@ARGV);

1	exec("$dir/myprog.sh",@ARGV);

This syntax does some important things: – passes a scalar value as the first argument which exec interprets as PROGRAM – passes an array as the second argument which exec will use as the arguments to pass into PROGRAM Note […]

Categories: How-To's, Technology Tags: Arg, Args, Argument, Arguments, bash, Exec, Execute, perl, Program, sh, Shell, System | No comments

How To Install/Update CPAN on MacOS Mojave with fatal error: ‘EXTERN.h’ file not found

Author: erics, June 12th, 2019

The Problem Tried to install the latest version of cpan and got stuck. Tracked it down to the dependency module Mac::SystemDirectory which was failing to build:

cpan[1]> install Mac::SystemDirectory                                                                                                                                                                                                                                                    
Reading '/var/root/.cpan/Metadata'
  Database was generated on Sun, 09 Jun 2019 07:17:02 GMT
Running install for module 'Mac::SystemDirectory'
Running make for E/ET/ETHER/Mac-SystemDirectory-0.10.tar.gz
Checksum for /var/root/.cpan/sources/authors/id/E/ET/ETHER/Mac-SystemDirectory-0.10.tar.gz ok
Scanning cache /var/root/.cpan/build for sizes
............................................................................DONE

  CPAN.pm: Building E/ET/ETHER/Mac-SystemDirectory-0.10.tar.gz

HASCOMPILEREZFt/TESTUSSI.c:2:10: fatal error: 'EXTERN.h' file not found
#include "EXTERN.h"
         ^~~~~~~~~~
1 error generated.
Couldn't execute cc  -g -pipe -fno-common -DPERL_DARWIN -fno-strict-aliasing -fstack-protector -Os "-I/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE"   -c HASCOMPILEREZFt/TESTUSSI.c -o HASCOMPILEREZFt/TESTUSSI.o: Inappropriate ioctl for device at Makefile.PL line 14.
Requires a compiler
Warning: No success on command[/usr/bin/perl Makefile.PL INC=-I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE]
  ETHER/Mac-SystemDirectory-0.10.tar.gz
  /usr/bin/perl Makefile.PL INC=-I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE -- NOT OK
Running make test
  Make had some problems, won't test
Running make install
  Make had some problems, won't install
Failed during this command:
 ETHER/Mac-SystemDirectory-0.10.tar.gz        : writemakefile NO '/usr/bin/perl Makefile.PL INC=-I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE' returned status 6400

cpan[1]> install Mac::SystemDirectory

Reading '/var/root/.cpan/Metadata'

Database was generated on Sun, 09 Jun 2019 07:17:02 GMT

Running install for module 'Mac::SystemDirectory'

Running make for E/ET/ETHER/Mac-SystemDirectory-0.10.tar.gz

Checksum for /var/root/.cpan/sources/authors/id/E/ET/ETHER/Mac-SystemDirectory-0.10.tar.gz ok

Scanning cache /var/root/.cpan/build for sizes

............................................................................DONE

CPAN.pm: Building E/ET/ETHER/Mac-SystemDirectory-0.10.tar.gz

HASCOMPILEREZFt/TESTUSSI.c:2:10: fatal error: 'EXTERN.h' file not found

#include "EXTERN.h"

^~~~~~~~~~

1 error generated.

Couldn't execute cc -g -pipe -fno-common -DPERL_DARWIN -fno-strict-aliasing -fstack-protector -Os "-I/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE" -c HASCOMPILEREZFt/TESTUSSI.c -o HASCOMPILEREZFt/TESTUSSI.o: Inappropriate ioctl for device at Makefile.PL line 14.

Requires a compiler

Warning: No success on command[/usr/bin/perl Makefile.PL INC=-I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE]

ETHER/Mac-SystemDirectory-0.10.tar.gz

/usr/bin/perl Makefile.PL INC=-I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE -- NOT OK

Running make test

Make had some problems, won't test

Running make install

Make had some problems, won't install

Failed during this command:

ETHER/Mac-SystemDirectory-0.10.tar.gz : writemakefile NO '/usr/bin/perl Makefile.PL INC=-I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE' returned status 6400

The Solution Use the MacOS installer command to deploy the needed files:

xcode-select --install
sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /
installer: Package name is macOS_SDK_headers_for_macOS_10.14
installer: Installing at base path /
installer: The install was successful.

xcode-select --install

sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /

installer: Package name is macOS_SDK_headers_for_macOS_10.14

installer: Installing at base path /

installer: The install was successful.

The, rerunning the cpan install works:

cpan[1]> install Mac::SystemDirectory                                                                                                                                                                                                                                                    
...
Running make install
Files found in blib/arch: installing files in blib/lib into architecture dependent library tree
Installing /Library/Perl/5.18/darwin-thread-multi-2level/auto/Mac/SystemDirectory/SystemDirectory.bs
Installing /Library/Perl/5.18/darwin-thread-multi-2level/auto/Mac/SystemDirectory/SystemDirectory.bundle
Installing /Library/Perl/5.18/darwin-thread-multi-2level/Mac/SystemDirectory.pm
Installing /usr/local/share/man/man3/Mac::SystemDirectory.3pm
Appending installation info to /Library/Perl/Updates/5.18.2/darwin-thread-multi-2level/perllocal.pod
  ETHER/Mac-SystemDirectory-0.10.tar.gz
  /usr/bin/make install  -- OK

cpan[1]> install Mac::SystemDirectory

...

Running make install

Files found in blib/arch: installing files in blib/lib into architecture dependent library tree

Installing /Library/Perl/5.18/darwin-thread-multi-2level/auto/Mac/SystemDirectory/SystemDirectory.bs

Installing /Library/Perl/5.18/darwin-thread-multi-2level/auto/Mac/SystemDirectory/SystemDirectory.bundle

Installing /Library/Perl/5.18/darwin-thread-multi-2level/Mac/SystemDirectory.pm

Installing /usr/local/share/man/man3/Mac::SystemDirectory.3pm

Appending installation info to /Library/Perl/Updates/5.18.2/darwin-thread-multi-2level/perllocal.pod

ETHER/Mac-SystemDirectory-0.10.tar.gz

/usr/bin/make install -- OK

Categories: How-To's, Technology Tags: 10.14, CPAN, Error, extern.h, Fatal, Fatal Error, File not found, Header, headers, howto, Install, installer, Libraries, Library, MacOS, Mojave, not found, Package, perl, pkg, System, tips, update, upgrade, XCode | No comments

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How To Process System Exit Codes Using Perl Eval

How To Properly Specify Command and Arguments to Exec in Perl

How To Install/Update CPAN on MacOS Mojave with fatal error: ‘EXTERN.h’ file not found

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