good chemistry is complicated, and a little bit messy -LW |
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Re: Slicing the output of a commandby TomDLux (Vicar) |
on Jul 10, 2015 at 02:42 UTC ( [id://1134073]=note: print w/replies, xml ) | Need Help?? |
Every once in a while, there is some activity which is relatively simple to perform using a shell command, but would be somewhat inconvenient using Perl commands. The down side is that it's generally sloppy. If you're going to get the contents of a file, and you're dealing with a very short throw-away script, it might make sense to `cat` it. But you're launching a shell (many milliseconds), opening the file (some milliseconds), loading all it's contents into memory, outputting the contents from the sub-process to the Perl script. If you open a file in Perl, it takes the same amount of time as when you do it in a sub-shell, even though you have to open() the file, <read> the contents, just no sub-shell. Just about anything you want to do, is available internally in Perl, either built-in, provided by a core module, or availaable as an add-on module. Go to Cpan.org or metacpan.org or search for what you need. For example, gzip-ing or gunzip-ing a file is as simple as use-ing the module, and specifying something in the open() command. As Occam said: Entia non sunt multiplicanda praeter necessitatem.
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