Author: devonenote

This note is for a trick to use Q and E  to escape characters for regular expression. You will find it very useful when you do string substitution and your pattern contains characters like slashes or backslashes .

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Say you have a directory d:bin and you want to add it to path environment at the beginning of your Perl script. Following code will do the trick.

my $dir="d:\bin";
$ENV{PATH}.=";$dir";

Then $dir will be included in new $ENV{PATH}

In Perl, you can execute external commands using system() or “. However, system and “ does not redirect command output to console and this results people who runs your perl script can’t see it. This also make debug much harder. Perl does not have a build in switch that equals to batch scripts’ “@echo on”, however this can be worked around by creating a ExecuteCommand subroutine.

sub ExecuteCommand {
my $cmd= $_;
my @cmdoutput = `$cmd`;
for $line (@cmdoutput) {
print $line;
}

Now just change your code from system($command) or `$command` to ExecuteCommand($command) and you will see all command output are redirected to console. (more…)