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string comparison

Posted on 2007-03-28
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Last Modified: 2010-03-05
$c = `$command`;
$name = "john";
if ($c !~ /Name: $name/gm) {
 print "fail \n";
}

The above command is not printing "fail"

the output of $command is:

Name: Jack
ID: 123
City: San Jose

0
Comment
Question by:perlperl
6 Comments
 
LVL 10

Expert Comment

by:xanius
ID: 18808276
Hi perlperl,

I've just tested your script. on my window box it works. Are you shure $command is doing what you want it to? Try:

$c = `$command`;
print "$command\n";
$name = "john";
if ($c !~ /Name: $name/gm) {
 print "fail \n";
}

to see if it in deed does whart you're expecting.

Cheers
Xanius
0
 

Author Comment

by:perlperl
ID: 18808305
Strange, when i try on different host...it works....unbelievable..both the host has same version of perl 5.6.0
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Expert Comment

by:xanius
ID: 18809488
Have you checked the output of $command on both hosts?
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Accepted Solution

by:
midrisi earned 500 total points
ID: 18810770
I assume your command returns output with "\n".So script will be as below:

@output=`command`;
$c=join("\n",@output); # this will glue your output as a single string
$name = "john";
if ($c !~ /Name: $name/gm) {
 print "fail \n";
}

I think this may solve your problem.
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LVL 48

Expert Comment

by:Tintin
ID: 18811696
You should *always*, *always* check the status of opening files and running system commands.

my $c = `command` or die "Can not run command because $!\n";
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LVL 84

Expert Comment

by:ozo
ID: 18817586
$c = `$command`;
is the same as
@output=`command`;
$c=join("",@output);

$c = `command` or die  doesn't test whether the command can be run, it tests whether the command had any output, (and not an output of "0")
you can test whether the command was run by checking $?

Unless $command had Name: john somewhere, in addition to
Name: Jack
ID: 123
City: San Jose
the snippet shold have printed
fail
Could there be something else in your program that is causing the problem?
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