bug of sh ?

[Tong Sun]

I don't know I've found a bug of sh or it is exactly the case it
should be:

The problme is mainly that, for the following script,
step1 p1 `lengthy shell invoking` p... >> output
step2 p1 `lengthy shell invoking` p... >> output
...
stepN p1 `lengthy shell invoking` p... >> output

the stepN will overwrite the output of stepN-1. And here is the detail:

The output of my script "myscript" is:

$ myscript
 printf "<h2><a href=reference/standard/0764580523/ewtoc.html>`perl -S 
title_get reference/standard/0764580523/ewtoc.html`</a></h2><br>\n"

 printf "<h2><a href=reference/standard/1576101762/ewtoc.html>`perl -S 
title_get reference/standard/1576101762/ewtoc.html`</a></h2><br>\n"

 printf "<h2><a href=reference/standard/1576101215/ewtoc.html>`perl -S 
title_get reference/standard/1576101215/ewtoc.html`</a></h2><br>\n"

The output of '>' is right:

$ myscript | sh > output
$ cat !$
<h2><a href=reference/standard/0764580523/ewtoc.html>JavaBeans: Table of 
Contents</a></h2><br>
<h2><a href=reference/standard/1576101762/ewtoc.html>Visual Developer SQL 
Database Programming with Java - Table of Contents</a></h2><br>
<h2><a href=reference/standard/1576101215/ewtoc.html>Web Developer's Guide to 
Java Beans - Table of Contents</a></h2><br>

But the output of ">>" is wrong:

$ rm output; myscript | sh -x >> output
++ perl -S title_get reference/standard/0764580523/ewtoc.html
+ printf '<h2><a href=reference/standard/0764580523/ewtoc.html>JavaBeans: Table 
of Contents</a></h2><br>\n'
++ perl -S title_get reference/standard/1576101762/ewtoc.html
+ printf '<h2><a href=reference/standard/1576101762/ewtoc.html>Visual Developer 
SQL Database Programming with Java - Table of Contents</a></h2><br>\n'
++ perl -S title_get reference/standard/1576101215/ewtoc.html
+ printf '<h2><a href=reference/standard/1576101215/ewtoc.html>Web 
Developer'\''s Guide to Java Beans - Table of Contents</a></h2><br>\n'

$ cat !$
<h2><a href=reference/standard/1576101762/ewtoc.html>Visual Developer SQL 
Database Programming <h2><a href=reference/standard/1576101215/ewtoc.html>Web 
Developer's Guide to Java Beans - Table of Contents</a></h2><br>

You see it should be right(like the previous result), but it
doesn't. So do you think it is a bug?



FYI, 

my debian:

$ cat /etc/debian_version
2.2


my "title_get" perl code:

- - - -
    require HTML::HeadParser;

    local $/;
    $text=<>;

    $p = HTML::HeadParser->new;
    $p->parse($text) and  print "not finished";

    print $p->header('Title');  # to access <title>....</title>
- - - -


-- 
SUN Tong