diff output; unix commands

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

I am writing a CGI script that uses the UNIX command, diff. I want to store the output of he diff command, so that I can manipulate it. Unfortunately, diff just keeps sending the output to standard out, the browser. I've tried:

my $foo = system("diff $args $file1 $file2");
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as well as

my $foo = `diff $args $file1 $file2`;
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Any suggestions? Thanks in advance

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Re: diff output; unix commands by bedk (Pilgrim) on Jan 23, 2002 at 23:33 UTC
`open FOO, "diff $args $file1 $file2 \|"` [download] then reading from <FOO> should do the trick.	[reply] [d/l]
Re: diff output; unix commands by webengr (Pilgrim) on Jan 24, 2002 at 00:08 UTC
I think that to make it work the way you tried, you need to have the call to diff return a list context. Try this, @lines = (`diff $args $file1 $file2`); for (@lines) { print; } [download] It may not be exactly what you want, in that it captures all of the output into an array. Or, if you really want the output from diff in a scalar as a single string, then you need to (temporarily) change the input record separator $/ to something other than newline, typically the null value will suffice. This snippet will accomplish the task: { local $/ = '\0'; $line = `diff $args $file1 $file2`; print $line; } [download] bedk's solution is probably better because you can filter the output from diff one line at a time through a regex, and save/process only the lines you want. Cheers, PCS	[reply] [d/l] [select]
Re: diff output; unix commands by PrakashK (Pilgrim) on Jan 24, 2002 at 04:07 UTC
If you can, use Text::Diff. `use Text::Diff; my $foo = Text::Diff::diff $file1, $file2, \%options;` [download] %options include STYLE (unified, context or classic etc), OUTPUT and a couple others. /prakash	[reply] [d/l]