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Full Discussion: How to set font color for STDIN,STDOUT and STDERR?
Top Forums UNIX for Advanced & Expert Users How to set font color for STDIN,STDOUT and STDERR? Post 302542402 by Corona688 on Wednesday 27th of July 2011 12:27:16 PM
Old 07-27-2011
The terminal can't tell what's printing to standard output vs standard error -- they both go to literally the same file. You could intercept standard error with a fifo and process it...
Code:
#!/bin/bash

# On exit, close stderr and delete the fifo so we don't leave dangling background processes.
trap "exec 2<&- ; rm ~/.tmpfifo" EXIT

rm -f ~/.tmpfifo

mkfifo ~/.tmpfifo
# Create a subshell that reads from fifo, writes to stderr.
# it gets its own copy of stderr, so redirecting stderr later won't change this.
(       while read LINE
        do
                printf "\x1b[01;31m%s\x1b[01;m\n" "$LINE"
        done < ~/.tmpfifo ) &

exec 2>~/.tmpfifo

# Thing that should print standard error in red
touch /

Code:
$ ./errfilter.sh
touch: setting times of `/': Permission denied
$

This only works for scripts, not for interactive terminals, because bash frequently uses stderr for its own things when in interactive mode.

---------- Post updated at 10:27 AM ---------- Previous update was at 10:11 AM ----------

Actually, here's a way that'll work in interactive mode:

Code:
trap "exec 5>~/.tmpfifo-$$ ; rm -f ~/.tmpfifo-$$ ; exec 5<&-" EXIT

mkfifo ~/.tmpfifo-$$

(       while [ -e ~/.tmpfifo-$$ ]
        do
                while read LINE
                do
                        printf "\x1b[01;31m%s\x1b[01;m\n" "$LINE"
                done < ~/.tmpfifo-$$ >&2
        done
 ) &

function err
{
        "$@" 2>/.tmpfifo-$$
}

Do this in your shell:
Code:
$ source errfilter.sh
$ err touch /
touch: setting times of `/': Permission denied
$

and any commands you run with err will have stderr color-coded.
This User Gave Thanks to Corona688 For This Post:
ungalnanban
 

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LEARN ABOUT SUSE

log::log4perl::appender::screen

Appender::Screen(3)					User Contributed Perl Documentation				       Appender::Screen(3)

NAME

       Log::Log4perl::Appender::Screen - Log to STDOUT/STDERR

SYNOPSIS

	   use Log::Log4perl::Appender::Screen;

	   my $app = Log::Log4perl::Appender::Screen->new(
	     stderr    => 0,
	     utf8      => 1,
	   );

	   $file->log(message => "Log me
");

DESCRIPTION

       This is a simple appender for writing to STDOUT or STDERR.

       The constructor "new()" take an optional parameter "stderr", if set to a true value, the appender will log to STDERR.  The default setting
       for "stderr" is 1, so messages will be logged to STDERR by default.

       If "stderr" is set to a false value, it will log to STDOUT (or, more accurately, whichever file handle is selected via "select()", STDOUT
       by default).

       Design and implementation of this module has been greatly inspired by Dave Rolsky's "Log::Dispatch" appender framework.

       To enable printing wide utf8 characters, set the utf8 option to a true value:

	   my $app = Log::Log4perl::Appender::Screen->new(
	     stderr    => 1,
	     utf8      => 1,
	   );

       This will issue the necessary binmode command to the selected output channel (stderr/stdout).

COPYRIGHT AND LICENSE

       Copyright 2002-2009 by Mike Schilli <m@perlmeister.com> and Kevin Goess <cpan@goess.org>.

       This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

perl v5.12.1							    2010-02-07						       Appender::Screen(3)
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