Execute shell commands, capture output problem

[CJason]

All,

I have the following snippet of perl code:

@results = `make abc.exe 2>&1 | grep -P '((undefined reference to|\.exe)\s)'`;

This command works fine from the shell prompt, but within my perl script nothing is returned into @results?? Any ideas on why this is the case...and what to do about it?

Thanks in advance!

 

[travs69]

Give full path's to everything to start with. Full path to make, abc.exe, grep etc..


Travis

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Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[CJason]

Tried adding the paths...still doesn't work. FYI: The code above works fine until I add the "| grep ....". That is, the make output lines get put into the array just fine without the pipe portion. Any other ideas?

 

[travs69]

you probably need to escape out your \'s. Perl see's one \ and assumes you are trying to escape what is after it to try \\ or \\\ I can't remember

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[CJason]

That was it!! Here is the WORKING code:

@results = `make abc.exe 2>&1 | grep -P '((undefined reference to|\\.exe)\\s)'`;

Thanks for your help!!

 

[travs69]

i still say put the full paths to everything

I had a whole site full of scripts and the user they ran as somehow had it's paths blow away.. things went CRAZY!!

I full path everything now.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[CJason]

But, what if the paths change...i.e., you run the script on a different platform? You may have to go thru and change all the paths, correct? If you leave the paths off...you should be good to go on any platform, correct?

 

[travs69]

no.. because even on a lot of platforms you might call ssh or something and there could be different versions (We have like 5 versions of ssh on one server for some reason). I don't want to depend on the fact that the user it is running on "happens" to have the paths I want.

At the beginning of my scripts I have a lot of things like
my $gzip = '/usr/bin/gzip';
my $gzcat = '/usr/bin/gzcat';
my $grep = '/usr/bin/grep';
my $ssh = '/usr/bin/ssh';

When I have to move from solaris to linux all I usually need to do is check and make sure they exist. For example on linux you normally don't have gzcat but you have zcat so I don't have to change my whole script, I just change the path for $gzcat.

All I can say is it has caused me more trouble not doing it, then doing it

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;