Storing system grep's output to an array in perl

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

Replies are listed 'Best First'.
Re: Storing system grep's output to an array in perl by rjt (Curate) on Mar 07, 2013 at 12:26 UTC
The pure Perl solution will be faster, more portable, and much sexier (substitute your actual filehandle opened with open for `<DATA>`): `#!/usr/bin/env perl use 5.010; use warnings; my @times = map { /^(?:top - (..:..:..))/ } <DATA>; say for @times; __DATA__ top - 00:35:18 up top - 01:23:45 other junk completely different format altogether not - 01:23:45 can't fool me! top - 02:35:46 top - 03:46:07` [download] Output: `00:35:18 01:23:45 02:35:46 03:46:07` [download]	[reply] [d/l] [select]
Re: Storing system grep's output to an array in perl by rnewsham (Curate) on Mar 07, 2013 at 11:41 UTC
The horrible way, which I do not recommend, would be to shell out with backticks my @tops = `/bin/grep -i "top-" filename \| /usr/bin/awk '(print $3)'`; [download] A better way would be something like `my @tops; open FILE, "<filename" or die "could not open filename"; while ( <FILE> ) { if ( m/^top \- (\d{2}:\d{2}:\d{2})/ ) { push @tops, $1; } } close FILE;` [download]	[reply] [d/l] [select]
Re^2: Storing system grep's output to an array in perl by SuicideJunkie (Vicar) on Mar 07, 2013 at 19:03 UTC
Or even better: `my @tops; open my $inputFileHandle, '<', $filename or die "could not open '$file +name', because the OS said: $!"; while ( <$inputFileHandle> ) { if ( m/^top \- (\d{2}:\d{2}:\d{2})/ ) { push @tops, $1; } }` [download]	[reply] [d/l]
Re: Storing system grep's output to an array in perl by arnaud99 (Beadle) on Mar 07, 2013 at 11:52 UTC
Hi A similar approach to the one above use strict; use warnings; my @all_times; while (my $line = <DATA>) { if ($line =~ /^top - /) { chomp $line; my ($top, $dash, $time, @rest) = split /\s+/, $line; push @all_times, $time; } } for (@all_times) { print $_, "\n"; } __DATA__ top - 00:35:18 up... blah blah blah ..... top - 00:35:15 up... fwertwe blah blah blah ..... blah blah blah ..... blah blah blah ..... blah blah blah ..... blah blah blah ..... top - 00:35:20 up... blah blah blah ..... top - 00:35:22 up... blah blah blah ..... top - 00:35:30 up... blah blah blah ..... [download] Output is: `00:35:18 00:35:15 00:35:20 00:35:22 00:35:30` [download] Arnaud	[reply] [d/l] [select]
Re: Storing system grep's output to an array in perl by vinoth.ree (Monsignor) on Mar 07, 2013 at 11:32 UTC
system() executes the command specified but it doesn't capture the output of the command. system() will return the exit status of the command as returned by the 'wait' call. Update: Use backtick(``) to capture the specified command's output. my @array = `grep -i "top-" filename \| awk '(print $3)'`;	[reply] [d/l]
Re: Storing system grep's output to an array in perl (perlfaq8) by Anonymous Monk on Mar 07, 2013 at 11:36 UTC
Hi, perlfaq -> perlfaq8 -> Why can't I get the output of a command with system()? The Perl Monks Guide to the Monastery, Tutorials: Perl documentation documentation, Searching Perl Documentation	[reply]
Re^2: Storing system grep's output to an array in perl (perlfaq8) by Anonymous Monk on Mar 07, 2013 at 11:37 UTC
fixed link :) Why can't I get the output of a command with system()?	[reply]
Re: Storing system grep's output to an array in perl by Anonymous Monk on Mar 12, 2013 at 10:59 UTC
Thank u monks...	[reply]
Re: Storing system grep's output to an array in perl by Anonymous Monk on Mar 12, 2013 at 11:01 UTC
Thnks a lot monks!	[reply]

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