Automatic generation of textfiles (tamaguchi)

Automatic generation of textfiles

tamaguchi

created: 2006-02-03 07:54:59

perlmonks

node
author

prlmnks

node
author

I have the problem. I would like to be able to automaticly generate many outfiles in .txt format in a forloop. Quite similar to when I write "program.pl >outfile.txt" in the command window, exept that now I have to generate many outfiles. Do you have an idea how to create the textfiles automaticly? Thanks for any help.

Re: Automatic generation of textfiles

tirwhan

created: 2006-02-03 08:06:38

perlmonks

prlmnks

I suggest you take a look at perldoc -f open and your questions should be answered.

Dogma is stupid.

Re: Automatic generation of textfiles

idle

created: 2006-02-03 08:31:12

perlmonks

prlmnks

You can use exec or system: exec(':> $filename');

Re^2: Automatic generation of textfiles

Fletch

created: 2006-02-03 08:35:15

perlmonks

prlmnks

While it's possible in shells to use exec to reopen descriptors, Perl's exec is a different beast. You'll either replace your running program with a very short lived shell, or you'll spawn a child shell which won't affect the parent process' file descriptors in any way.

Re^3: Automatic generation of textfiles

idle

created: 2006-02-03 08:55:47

perlmonks

prlmnks

Maybe I get it wrong, but it seems to me that tamaguchi asked how to create files, not open.

Re^4: Automatic generation of textfiles

Fletch

created: 2006-02-03 09:06:23

perlmonks

prlmnks

The example he gave was using shell redirection to capture the output of his script. And even so, it's overkill to spawn another shell when a simple { open( my $fh, ">", $newfile ) or die "open $newfile: $!\n" } would suffice.

Re^4: Automatic generation of textfiles

blazar

created: 2006-02-04 06:59:55

perlmonks

prlmnks

$ mkdir foo
$ cd foo/
$ perl -e 'open F, ">bar"'
$ ls
bar

Re^2: Automatic generation of textfiles

blazar

created: 2006-02-03 08:47:51

perlmonks

prlmnks

Huh?!? Low and behold I'd just point him to

my %fh;
open $fh{$_}, '>', $_ 
  or die "Can't open `$_': $!\n"
  for @many_files;
# if they're not TOO many ;-)

Re: Automatic generation of textfiles

jonadab

created: 2006-02-03 08:42:30

perlmonks

prlmnks

tirwhan is right, but his link is taking forever to load, at least for me, so I'll add a little more information. Basically, you're looking for information on filehandles. You can open a file in output mode by doing something like open MYHANDLE, '>', $filename or die $!; and then you can write stuff to that open file with something like print MYHANDLE $stuff;

To create multiple files, just do that repeatedly. Some wording in your question leads me to believe you already know a way to do something repeatedly.

Sanity? Oh, yeah, I've got all kinds of sanity. Why, I've got so much sanity it's driving me crazy. In fact, I've developed whole new kinds of sanity.

Re: Automatic generation of textfiles

bart

created: 2006-02-03 09:00:49

perlmonks

prlmnks

If I understand you correctly, then what you're asking for is known in the Unix world as "tee". I remember having seen several solutions to solve this neatly, in Perl. In fact, it's even in the official perlfaq:
How do I print to more than one file at once?