Re^2: PDF output to temp file

`evince bill.pdf >> /home/administrator/temp_1`;

Using backticks here doesn't make sense, because due to the redirection, no output would be returned anyway. A better solution would be either

system('evince bill.pdf >> /home/administrator/temp_1');
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my $errmsg=`evince bill.pdf 2>&1 >> /home/administrator/temp_1`;
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Another alternative to consider is IPC::Run. This would spawn the command without the need of an auxiliary shell process.

--
Ronald Fischer <ynnor@mm.st>

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Re^3: PDF output to temp file by kcott (Archbishop) on Mar 22, 2012 at 11:16 UTC
Using backticks here doesn't make sense, because due to the redirection, no output would be returned anyway. I disagree. AM said that he wanted the output redirected: "I want to redirect the output of a terminal cmd on linux to a output file .". I wasn't about to make guesses based on his code. I did, however, point out issues with the code and queried his use of `$rc`. -- Ken	[reply] [d/l]
Re^4: PDF output to temp file by rovf (Priest) on Mar 22, 2012 at 14:23 UTC
The reason why I think `system` makes more sense than backticks in this example, is, that the usage of backticks implies that the output is used somehow. Think about readability: If we see in a code a backticked expression, where the value is not used, we think that maybe the code is not what the write had expected. If you use `system` instead, you communicate to the reader more clearly what's going on. Or, to approach it from a different perspective: Under what conditions would you choose, to use `system($cmd)` instead of `$cmd`? -- Ronald Fischer <ynnor@mm.st>	[reply] [d/l] [select]
Re^5: PDF output to temp file by kcott (Archbishop) on Mar 22, 2012 at 22:17 UTC
G'day Ronald, I think it's possible that we've both slightly misconstrued the other's intent and that this has been exacerbated with each response. I'll address both the general issue of `system($cmd)` vs. `$cmd` and then look at the more specific case raised by AM. In general, I avoid platform-specific code. On the rare occasions when this isn't the case, I'm more likely to choose `system($cmd)` for exactly the reasons you state: "you communicate to the reader more clearly what's going on". I believe we're in agreement with respect to this general case of usage. If I have a reason not to use `system()`, I'd normally choose `qx{$cmd}` over `$cmd`. AM's original question contained garbage code. I cobbled together various elements of what he had, to produce something which did what he asked for: `temp_1`, `>>/home/administrator` and `evince bill.pdf`; was munged into `evince bill.pdf >> /home/administrator/temp_1`;. I retained the append mode (`>>`) which he'd used although I'm not convinced that he didn't actually want write mode (`>`); similarly, I retained the backquotes. I stated that I didn't think he'd described what he really wanted and queried what he was using `$rc` for. -- Ken	[reply] [d/l] [select]