is there a way to find list of valid locales in my linux using perl?
This command will give you a list of locales: locale -a From a Perl script you can execute the same using system(“locale -a”);
perl
How is Perl’s @INC constructed?
We will look at how the contents of this array are constructed and can be manipulated to affect where the Perl interpreter will find module files. Default @INC The Perl interpreter is compiled with a specific default value for @INC. To find this value, run the command env -i perl -V (env -i ignores the … Read more
In Perl, how do I change, delete, or insert a line in a file, or append to the beginning of a file?
(This is the official perlfaq answer, minus any subsequent edits) The basic idea of inserting, changing, or deleting a line from a text file involves reading and printing the file to the point you want to make the change, making the change, then reading and printing the rest of the file. Perl doesn’t provide random … Read more
How do I get the Perl debugger to not stop at “100 levels deep in subroutine calls”
Add the line: $DB::deep = 500; # or more if necessary to the start of your program. The following program runs to completion in the debugger: use strict; use warnings; sub f($) { my $x = shift; print “$x\n”; if ($x < 200) { f(1 + $x); } } $DB::deep = 500; f(1); outputting: 198 … Read more
How can I capture multiple matches from the same Perl regex?
As Jim’s answer, use the /g modifier (in list context or in a loop). But beware of greediness, you dont want the .* to match more than necessary (and dont escape < = , they are not special). while($string =~ /<img\s+src=”https://stackoverflow.com/questions/2884549/(.*?)”/g ) { … }
How should I compare Perl references?
References, by default, numify to their addresses. Those reference addresses are unique for every reference, so it can often be used in equality checks. However, in the snippet you showed, you’d first have to make sure that both $ref1 and $ref2 are actually references. Otherwise you might get incorrect results due to regular scalars containing … Read more
Use of double negation (!!) [duplicate]
It converts non-boolean types to boolean (dualvar(0,””) or 1). It is a shortcut way of doing this, instead of trying to cast it explicitly (which may take more characters). The ! operator negates the truthness of its argument. Hence, two of them are used. Many object types are “truthy”, and others are “falsey”. The only … Read more
Kleene’s Star: why does $_ = “a”; s/a*/e/g produce: ee
Your analysis of why the results are “ee” and “ebe” is completely accurate. The “/g” modifier causes the regex to match once, and then try to match again from where the last match stopped. The reason for the discrepancy (it doesn’t replace the empty string to the left of “a”) is that is because “*” … Read more
In Perl, what is the difference between use and require for loading a module?
The use function: use ModuleName; is equivalent to the following code using the require function: BEGIN { require ModuleName; ModuleName->import; } The BEGIN block causes this code to run as soon as the parser sees it. The require loads the module or dies trying. And then the import function of the module is called. The … Read more
What is the best way to handle exceptions in Perl?
The consensus of the Perl community seems to be that Try::Tiny is the preferred way of doing exception handling. The “lenient policy” you refer to is probably due to a combination of: Perl not being a fully object-oriented language. (e.g. in contrast to Java where you can’t avoid dealing with exceptions.) The background of many … Read more