bash redirects
STDIN STDOUT STDERR
STDOUT to STDERR
ls zzz 1>&2
STDERR to STDOUT
ls zzz 2>&1
STDOUT to null and STDERR to STDOUT
ls zzz > /dev/null 2>&1
STDOUT and STDERR to null
ls zzz &> /dev/null
REFERRERS
BashShell
ls zzz 1>&2
ls zzz 2>&1
ls zzz > /dev/null 2>&1
ls zzz &> /dev/null