NAMEVERSIONDESCRIPTIONHow do I do (anything)? How can I use Perl interactively? How do I find which modules are installed on my system?
Let's take the same data file we worked with while learning to read a file in Perl, and we'll write to it this time. In order to write to a file in Perl.
How do I debug my Perl programs? How do I profile my Perl programs? How do I cross- reference my Perl programs? Is there a pretty- printer (formatter) for Perl?
#!/usr/bin/perl use MIME::Lite; $from = 'qwerty\@erweer.com'; $to = 'abcd\@efgh.com'; $Subject = 'Hello'; # Part using which the attachment is sent to an email # $msg. Writing to a file #!/usr/bin/perl use strict; use warnings; use Path::Class; use autodie; # die if problem reading or writing a file my $dir = dir('/tmp'); # /tmp my.
Summary: in this tutorial, you will learn how to read a file in scalar context and read the file using diamond operator (<>). Please follow the open file tutorial.
Is there an IDE or Windows Perl Editor? Where can I get Perl macros for vi? Where can I get perl- mode or cperl- mode for emacs?
How can I use curses with Perl? How can I write a GUI (X, Tk, Gtk, etc.) in Perl? How can I make my Perl program run faster? How can I make my Perl program take less memory? Is it safe to return a reference to local or lexical data?
How can I free an array or hash so my program shrinks? How can I make my CGI script more efficient? How can I hide the source for my Perl program? How can I compile my Perl program into byte code or C? How can I get #! perl to work on [MS- DOS,NT..]? Can I write useful Perl programs on the command line? Why don't Perl one- liners work on my DOS/Mac/VMS system?
- Perl file handling tutorial: learn to open, read, write and close files with Perl.
- File::Fetch. NAME; SYNOPSIS; DESCRIPTION; ACCESSORS; METHODS $ff = File::Fetch->new( uri => 'http:// $where = $ff->fetch( [to => /my.
- Perlfaq3. NAME; VERSION; DESCRIPTION. How do I do (anything)? How can I use Perl interactively? How do I find which modules are installed on my system? How do I debug.
- Reading and processing text files is one of the common tasks done by Perl. For example, often you encounter a CSV file (where CSV stand for Comma-separated values.
Where can I learn about CGI or Web programming in Perl? Where can I learn about object- oriented Perl programming? Where can I learn about linking C with Perl? I've read perlembed, perlguts, etc., but I can't embed perl in my C program; what am I doing wrong? When I tried to run my script, I got this message. What does it mean?
What's Make. Maker? AUTHOR AND COPYRIGHTNAMEperlfaq. Programming Tools. VERSIONversion 5. DESCRIPTIONThis section of the FAQ answers questions related to programmer tools. How do I do (anything)?
Have you looked at CPAN (see perlfaq. The chances are that.
Have you read the appropriate manpages? Here's a brief index: Basics. Execution. Functions. Objectsperlref - Perl references and nested data structuresperlmod - Perl modules (packages and symbol tables)perlobj - Perl objectsperltie - how to hide an object class in a simple variable.
Data Structuresperlref - Perl references and nested data structuresperllol - Manipulating arrays of arrays in Perlperldsc - Perl Data Structures Cookbook. Modulesperlmod - Perl modules (packages and symbol tables)perlmodlib - constructing new Perl modules and finding existing ones.
Regexesperlre - Perl regular expressionsperlfunc - Perl builtin functions> perlop - Perl operators and precedenceperllocale - Perl locale handling (internationalization and localization)Moving to perl. Linking with Cperlxstut - Tutorial for writing XSUBsperlxs - XS language reference manualperlcall - Perl calling conventions from Cperlguts - Introduction to the Perl APIperlembed - how to embed perl in your C program. Varioushttp: //www. FMTEYEWTK. tgz. (not a man- page but still useful, a collection of various essays on. Perl techniques)A crude table of contents for the Perl manpage set is found in perltoc. How can I use Perl interactively?
The typical approach uses the Perl debugger, described in the. Now just type in any legal Perl code, and it will be immediately. You can also examine the symbol table, get stack. You can also use Devel: :REPL which is an interactive shell for Perl.
REPL - Read, Evaluate, Print, Loop. It provides. various handy features. How do I find which modules are installed on my system? From the command line, you can use the cpan. You can also use cpan.
Inside a Perl program, you can use the Ext. Utils: :Installed module to. The standard library which comes with Perl just shows up. Perl" (although you can get those with Module: :Core. List). use. Ext. Utils: :Installed; my$inst = Ext. Utils: :Installed- > new(); my@modules = $inst- > modules(); If you want a list of all of the Perl module filenames, you.
File: :Find: :Rule: use. File: :Find: :Rule; my@files = File: :Find: :Rule- > extras({follow=> 1})- > file()- > name('*. INC); If you do not have that module, you can do the same thing. File: :Find which is part of the standard library: use. File: :Find; my@files; find({wanted=> sub{push@files,$File: :Find: :fullnameif - f $File: :Find: :fullname & & /\. INC); printjoin"\n",@files; If you simply need to check quickly to see if a module is.
If you can. read the documentation the module is most likely installed. If you cannot read the documentation, the module might not.
Module: :Name. You can also try to include the module in a one- liner to see if. MModule: :Name - e. If you don't receive a "Can't locate .. INC" error message, then Perl.
How do I debug my Perl programs?(contributed by brian d foy)Before you do anything else, you can help yourself by ensuring that. Perl tell you about problem areas in your code. By turning. on warnings and strictures, you can head off many problems before. You can find out more about these in strict. Beyond that, the simplest debugger is the print function. Use it. to look at values as you run your program: print. STDERR"The value is [$value]\n"; The Data: :Dumper module can pretty- print Perl data structures: use.
Data: :Dumperqw( Dumper ); print. STDERR"The hash is " . Dumper( \%hash) .
Perl comes with an interactive debugger, which you can start with the. It's fully explained in perldebug. If you'd like a graphical user interface and you have Tk, you can use. It's on CPAN and available for free. If you need something much more sophisticated and controllable, Leon.
Brocard's Devel: :ebug (which you can call with the - D. Debug. gives you the programmatic hooks into everything you need to write your. You can also use a commercial debugger such as Affrus (Mac OS X), Komodo. Activestate (Windows and Mac OS X), or EPIC (most platforms). How do I profile my Perl programs?(contributed by brian d foy, updated Fri Jul 2. PDT 2. 00. 8)The Devel. Perl programs. The Devel: :NYTProf (New York Times Profiler) does both statement.
It's available from CPAN and you also invoke. NYTProfsome_perl. It creates a database of the profile information that you can turn into. The nytprofhtml. command turns the data into an HTML report.
Devel: :Cover report: nytprofhtml. You might also be interested in using the Benchmark to.
You can read more about profiling in Programming Perl, chapter 2. Mastering Perl, chapter 5. The Perl Journal, "Creating a Perl Debugger". Profiling in Perl". Perl. com has two interesting articles on profiling: "Profiling Perl".
Simon Cozens, http: //www. Debugging and. Profiling mod_perl Applications", by Frank Wiles. Randal L. Schwartz writes about profiling in "Speeding up Your Perl. Programs" for Unix Review. Unix. Review/col.
Profiling. in Template Toolkit via Overriding" for Linux Magazine. Linux. Mag/col. 75. How do I cross- reference my Perl programs?
The B: :Xref module can be used to generate cross- reference reports. Perl programs. perl - MO=Xref[,OPTIONS]scriptname. Is there a pretty- printer (formatter) for Perl? Perl: :Tidy comes with a perl script perltidy which indents and.
Perl scripts to make them easier to read by trying to follow. If you write Perl, or spend much time reading. Perl, you will probably find it useful. Of course, if you simply follow the guidelines in perlstyle.
The habit of formatting your code. Your editor can and should.
The perl- mode or newer cperl- mode for emacs. Tom Christiansen and many other VI users swear by. O {^M}^[O^TPut that in your . In insert mode, ^T is. D is for undenting, and ^O is for blockdenting- -as. A more complete example, with comments, can be found at. TOMC/scripts/toms.
Is there an IDE or Windows Perl Editor? Perl programs are just plain text, so any editor will do. If you're on Unix, you already have an IDE- -Unix itself.
The Unix. philosophy is the philosophy of several small tools that each do one. It's like a carpenter's toolbox. If you want an IDE, check the following (in alphabetical order, not. Eclipsehttp: //e- p- i- c. The Eclipse Perl Integration Project integrates Perl. Eclipse. Enginsitehttp: //www.
Perl Editor by Eng. In. Site is a complete integrated development. IDE) for creating, testing, and debugging Perl scripts. Windows 9x/NT/2. 00. XP or later. Kephrahttp: //kephra.
GUI editor written in Perl using wx. Widgets and Scintilla with lots of smaller features.
Aims for a UI based on Perl principles like TIMTOWTDI and "easy things should be easy. Komodohttp: //www. Active. State. com/Products/Komodo/Active. State's cross- platform (as of October 2.
Windows, Linux. and Solaris), multi- language IDE has Perl support, including a regular expression. Notepad++http: //notepad- plus. Open Perl IDEhttp: //open- perl- ide. Open Perl IDE is an integrated development environment for writing. Perl scripts with Active.
State's Active. Perl distribution. Windows 9. 5/9. 8/NT/2. Opti. Perlhttp: //www. Opti. Perl is a Windows IDE with simulated CGI environment, including.
Padrehttp: //padre. Padre is cross- platform IDE for Perl written in Perl using wx. Widgets to provide. It's open source under the Artistic License.
It. is one of the newer Perl IDEs. Perl. Builderhttp: //www. Perl. Builder is an integrated development environment for Windows that. Perl development. Perl+http: //helpconsulting.
From Help Consulting, for Windows. Visual Perlhttp: //www. Products/Visual_Perl/Visual Perl is a Visual Studio. NET plug- in from Active. State. Zeushttp: //www. Zeus for Windows is another Win.
IDE. that comes with support for Perl. For editors: if you're on Unix you probably have vi or a vi clone. In any emacs the cperl- mode (M- x cperl- mode) gives you. Perl editing mode in any editor. If you are using Windows, you can use any editor that lets you work. Note. Pad or Word.
Pad. Word processors, such as. Microsoft Word or Word. Perfect, typically do not work since they insert.
Text Only". You can also download text editors designed. Textpad (. http: //www.
Ultra. Edit ( http: //www. If you are using Mac. OS, the same concerns apply. Mac. Perl (for Classic. Popular external editors are. BBEdit ( http: //www.
Alpha (. http: //www. Alpha/Alpha. 8. html ). Mac. OS X users can use. Unix editors as well. The following are Win.
IDEs that support Perl: There is also a toyedit Text widget based editor written in Perl. Tk module on CPAN. The ptkdb. ( http: //ptkdb. Perl/Tk- based debugger that. Perl Composer. ( http: //perlcomposer.
How to Read and Write Files in Perl. Writing to a File in Perl. November 1. 3, 2. Let's take the same data file we worked with while learning to read a file in Perl, and we'll write to it this time. In order to write to a file in Perl, you must open a filehandle and point it at the file you're writing.
If you're using Unix, Linux, or a Mac, you might also need to double check your file permissions to see if your Perl script is allowed to write to the data file. MYFILE, '> > data. MYFILE "Bob\n". close (MYFILE).
If you run this program, then run the program from the previous example on reading a file in Perl, you'll see that it's added one more name to the list. Larry. Moe In fact, every time you run the program it will add another Bob to the end of the file. This is happening because we opened the file in append mode.
To open a file in append more, just prefix the filename with the > > symbol. This tells the open function that you want to write to the file by tacking more onto the end of it. If instead you want to overwrite the existing file with a new one, you can use the > single greater than symbol to tell the open function that you want a fresh file each time. Try replacing the > > with a > and you'll see that your data. Bob - each time you run the program.
MYFILE, '> > data. Next we use the print function to print our new name to the file. You print to a filehandle simply by following the print statement with the filehandle.
MYFILE "Bob\n"; Finally we close the filehandle to finish out the program. MYFILE); Previous: Reading a file in Perl. This site uses cookies.
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