UNIX for Advanced & Expert Users

$date
Wed Jul 27 12:36:50 IST 2011
$datee
bash: datee: command not found
$alias ls
alias ls='ls --color=auto -F '
$aliass ls
bash: aliass: command not found

#!/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 /

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

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-$$
}

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

command 2> >(while read line; do echo -e "\e[01;31m$line\e[0m"; done)