output reassignment/redirection

[mark-casey]

Might be nice to be able to specify a specific line of text or a regular expression that if matched could be moved to stderr or stdout.

For example if you have an rsync job that runs frequently and you know, for whatever reason, that there will always be a given file that will be locked or will have vanished during the transfer.

Then you could move that specific information to stdout to avoid getting emails for things you don't care about.

[mark-casey]

an early effort to move output containing the word Resource from stderr to stdout... (test.sh just echo'ed some lines that said "Copying" to stdout and one that said "Resource not found" to stderr)

mkfifo /tmp/e2o
cat <( ./test.sh 2> >( tee >(grep Resource 1>/tmp/e2o) | grep -v Resource ) & cat 0</tmp/e2o ) | grep -v Resource

[mark-casey]

later effort. Doesn't work if you take the sleep lines out, because the greps finish out of order...

#!/bin/bash

exec 6>&1
exec 7>&2

exec 2> >( tee >(grep --line-buffered Resource\ temporarily\ unavailable >&6) | grep --line-buffered -v Resource\ temporarily\ unavailable >&7 )
exec > >( tee >(grep --line-buffered Copying\ cool\ stuff >&7) | grep --line-buffered -v Copying\ cool\ stuff >&6 )

echo "$0: OUT filler0"
sleep .1
echo "$0: OUT filler1"
sleep .1
echo "$0: ERR filler2" >&2
sleep .1
echo "$0: OUT filler3"
sleep .1
echo "$0: OUT filler4"
sleep .1
echo "$0: ERR filler5" >&2
sleep .1
echo "$0: OUT filler6"
sleep .1
echo "$0: Copying cool stuff7"
sleep .1
echo "$0: failed!!: Resource temporarily unavailable (11)8" >&2
sleep .1
echo "$0: Copying cool stuff9"
sleep .1
echo "$0: OUT filler10"
sleep .1
echo "$0: ERR filler11" >&2
sleep .1
echo "$0: OUT filler12"
sleep .1
echo "$0: OUT filler13"

exec 3>&-
exec 4>&-
exec 6>&-
exec 7>&-

exit 0