thor has asked for the wisdom of the Perl Monks concerning the following question:

Hello all, I've a question for you to ponder. I have recently written a script to rip through a log file, pick out interesting tidbits, and display them in a report, depending on what type of tidit it is. I have all of my reports being called in subroutines, and call them all in succession. My problem is that in the final report, there is a "^L" at the beginning of each report. Is there something that I am doing incorrectly? Here is a sample of one of my subroutines (they are all the same, except for the header and the data they use) 
sub DepOverrideRpt {
my ($i,$temp);
format DepOverride_Hdr=
Dependencies Overriden
=======================
     Job     |  Time
-------------|---------
.
my($key, $job, $time);
format DepOverride=
@<<<<<<<<<<<<|@>>>>>>>>
$job,$time
.
$temp=select(OUTFILE);
$~="DepOverride";
$^="DepOverride_Hdr";
$-=0;
select($temp);
foreach $i (0 .. 1)
{
 foreach $key (sort {$o_override[$i]{$a} cmp $o_override[$i]{$b} } key
+s %{$o_override[$i]})
 {
 $job=$key;
 $time=$o_override[$i]{$key};
 write OUTFILE;
 }
}
print OUTFILE "=======================\n\n";
}

[download]
In the above example @o_override is an array of hashes used to store data from different days (%o_override[0] is a hash containing data from 6am - midnight on day 1, %o_override contains data from midnight to 6am on day 2) Any help would be appreciated, thor

Replies are listed 'Best First'.
Re: Control Characters in reports...
by McD (Chaplain) on Feb 23, 2001 at 02:08 UTC
    thor writes:

    My problem is that in the final report, there is a "^L" at the beginning of each report.

    Yup. That's a "Form feed" - you get 'em for free with write. According to Programming Perl (2nd Ed),

    Top-of-form processing is handled automatically: if there is insufficient room on the current page for the formatted record, the page is advanced by writing a form feed,

    When you set $- to zero, you're forcing a new "page", and hence ^L, on every write. Tinkering with that and $= ought to let you get rid of the ^L problem.

    Peace,
    -McD

[reply]
[d/l]
[select]
      Thanks for the info. Now the problem is getting everything to print out. It seems that if I set $- to anything but zero, the header won't print, but everything else prints without the form feed. My question now is: how is $- used? The way that I am thinking of it is every write that is performed, perl checks against $- and determines whether it can get that line on the current page or not. Am I correct in this? Thanks, thor
[reply]
        I just found a cheat. If you set $^L = "", the form feeds disappear! Yeah. thor
[reply]

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