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How do I do a tail -f in perl?

by faq_monk (Initiate)
on Oct 13, 1999 at 03:42 UTC ( #814=perlfaq nodetype: print w/replies, xml ) Need Help??

Current Perl documentation can be found at perldoc.perl.org.

Here is our local, out-dated (pre-5.6) version:

First try

    seek(GWFILE, 0, 1);

The statement seek(GWFILE, 0, 1) doesn't change the current position, but it does clear the end-of-file condition on the handle, so that the next <GWFILE> makes Perl try again to read something.

If that doesn't work (it relies on features of your stdio implementation), then you need something more like this:

        for (;;) {
          for ($curpos = tell(GWFILE); <GWFILE>; $curpos = tell(GWFILE)) {
            # search for some stuff and put it into files
          }
          # sleep for a while
          seek(GWFILE, $curpos, 0);  # seek to where we had been
        }

If this still doesn't work, look into the POSIX module. POSIX defines the clearerr() method, which can remove the end of file condition on a filehandle. The method: read until end of file, clearerr(), read some more. Lather, rinse, repeat.

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[shmem]: I see that there is a plugin geany-plugin- codenav
[shmem]: maybe that supports ctags, check the documentation
[Lady_Aleena]: I'd have to talk to a geany person to see.
[Lady_Aleena]: Right now, I'm trying to decide whether I want to rewrite how variables are entered in the sub I'm working on.
[shmem]: wait, what? you want that person to read the documentation for you?
[Lady_Aleena]: I might have to go with options instead of a straight list.
[Discipulus]: if more than 3 go for named variables LA
[Lady_Aleena]: Discipulus, it is at 2 now, but with what I am thinking about, it could go to 3. However, only 1 is needed. The second and third are optional.
[shmem]: straight list or named parameters - that depends on whether (and how many) optional arguments you have
[Discipulus]: if so a plain list is ok, imho

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