Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl-Sensitive Sunglasses
 
PerlMonks  

comment on

( [id://3333] : superdoc . print w/replies, xml ) Need Help??
A program doesn't have to know if it's writing to a FIFO or not, unless you're dealing with networked files, i.e. files on some NFS or SMB like share. The only issue I can see here is that opening a FIFO for writing usually requires a listener, so if your filter application crashes (or you don't start it) your program is likely to have issues (some SIGPIPE in the first case, hanging in the second). Another possible issue deals with the limited buffer between these applications, so you must ensure that your filter program doesn't lose time possibly blocking the log producer.

The FIFO solution leaves the duty to write the logs to the Perl filter, not to the original application, and the filter is likely to write regular files - something that a logrotate program should not be upset with.

As for the redirection, I don't really understand how it should work. Redirecting STDOUT to STDERR means that you basically lose them all in the listener application. The pipeline

producer | consumer
links producer's STDOUT to consumer's STDIN, so the suggested redirection leaves you with an empty STDIN and nowhere to read log lines from.

Flavio
perl -ple'$_=reverse' <<<ti.xittelop@oivalf

Don't fool yourself.

In reply to Re^2: removing lines from a file by polettix
in thread removing lines from a file by ministry

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.