The built-in variables @- and @+ hold the start and end positions, respectively, of the last successful match. $-[0] and $+[0] correspond to entire pattern, while $-[N] and $+[N] correspond to the $N ($1, $2, etc.) submatches.
It’s a nasty little idiom for setting autoflush on a filehandle other than STDOUT. select() takes the supplied filehandle and (basically) replaces STDOUT with it, and it returns the old filehandle when it’s done. So (select($s),$|=1) redirects the filehandle (remember select returns the old one), and sets autoflush ($| = 1). It does this in … Read more
I can only speak for Debian. The two programs are called /usr/bin/rename.ul from the util-linux package (hence the .ul suffix) /usr/bin/prename from the perl package The actual rename command works via the /etc/alternatives mechanism, whereby /usr/bin/rename is a symlink to /etc/alternatives/rename /etc/alternatives/rename is a symlink to /usr/bin/prename The same problem has been bugging me on … Read more
You can turn relative paths into full paths using readlink -f foo. So you would do something like: ln -s $(readlink -f $origlink) $newlink rm $origlink EDIT: I noticed that you wish to keep the paths relative. In this case, after you move the link, you can use symlinks -c to convert the absolute paths … Read more
From this page here: http://perldoc.perl.org/perlop.html#Logical-Defined-Or Although it has no direct equivalent in C, Perl’s // operator is related to its C-style or. In fact, it’s exactly the same as ||, except that it tests the left hand side’s definedness instead of its truth. Thus, EXPR1 // EXPR2 returns the value of EXPR1 if it’s defined, … Read more
open my $file, ‘<‘, “filename.txt”; my $firstLine = <$file>; close $file;
That’s what backticks are for. From perldoc perlfaq8: Why can’t I get the output of a command with system()? You’re confusing the purpose of system() and backticks (“). system() runs a command and returns exit status information (as a 16 bit value: the low 7 bits are the signal the process died from, if any, … Read more
1024 in decimal is not 0xFF in hex. Instead, it is 0x400. You can use sprintf as: my $hex = sprintf(“0x%X”, $d);
Use the caller() function: my $sub_name = (caller(0))[3]; This will give you the name of the current subroutine, including its package (e.g. ‘main::test’). Closures return names like ‘main::__ANON__’and in eval it will be ‘(eval)’.
The most important feature of an IDE for Perl development (including Padre) is: an interactive debugger that actually works. E.g. remembering breakpoints, ability to drill down into complicated data structures, and copy (to clipboard) should work on watched variables – including a menu command Copy Special that allows putting it in various formats; say CSV, … Read more