Re: capturing stderr of echo piped to a file

Your redirection is in the wrong order:

my $command = "echo $writeline >> $file";
my $output = `$command 2>&1`;
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Writing that out, you end up with

my $output = `$command echo $writeline >> $file 2>&1`;
[download]

Which means redirect STDOUT to the file, then STDERR to (current) STDOUT, i.e. also to the file. You probably want

my $output = `$command echo $writeline 2>&1 >> $file`;
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instead, i.e. redirect STDERR to STDOUT, then STDOUT (but not the redirected STDERR) to the file.

Comment on Re: capturing stderr of echo piped to a file Select or Download Code

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Re^2: capturing stderr of echo piped to a file by boftx (Deacon) on Oct 29, 2014 at 18:58 UTC
Your statement is simply not true. The order of the redirects doesn't matter and in my experience having `2>&1` at the end of the line is much more common. A simple test on the command line with a perl script that issues a warn as well as a print statement will demonstrate this. You must always remember that the primary goal is to *drain the swamp* even when you are hip-deep in alligators.	[reply] [d/l]
Re^3: capturing stderr of echo piped to a file by Crackers2 (Parson) on Oct 29, 2014 at 19:17 UTC
Perhaps you should just try it? `> { echo out; echo err >&2; } >f1 2>&1 > cat f1 out err > { echo out; echo err >&2; } 2>&1 >f1 err > cat f1 out` [download] Redirection order definitely DOES matter in the shell. (Hmm, unless it's shell-specific? I'm using bash) And just to do exactly what you said.. `> perl -e'print "print\n"; warn "warn"' >f1 2>&1 > cat f1 warn at -e line 1. print > perl -e'print "print\n"; warn "warn"' 2>&1 >f1 warn at -e line 1. > cat f1 print` [download] In the first case both print and warn go to the file, in the second case warn goes to stdout and print to the file.	[reply] [d/l] [select]
Re^4: capturing stderr of echo piped to a file by boftx (Deacon) on Oct 29, 2014 at 19:26 UTC
`~/stuff > perl foobar.pl Normal STDOUT Going to STDERR ~/stuff > echo 'Just a starting point > ' >JGBtest.txt ~/stuff > cat JGBtest.txt Just a starting point ~/stuff > perl foobar.pl >>JGBtest.txt 2>&1 ~/stuff > cat JGBtest.txt Just a starting point Going to STDERR Normal STDOUT ~/stuff > cat foobar.pl #!/usr/bin/perl use warnings; use strict; print "Normal STDOUT\n"; warn "Going to STDERR\n"; exit; __END__ ~/stuff >` [download] You must always remember that the primary goal is to *drain the swamp* even when you are hip-deep in alligators.	[reply] [d/l]
Re^5: capturing stderr of echo piped to a file by Crackers2 (Parson) on Oct 29, 2014 at 20:13 UTC
Re^6: capturing stderr of echo piped to a file by boftx (Deacon) on Oct 29, 2014 at 23:21 UTC
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