Run any command and suppress its output to stdin and stderr, unless it returns an error code.

quiet.sh

#!/usr/bin/env bash

# Run any command and suppress its output to stdin and stderr, unless it returns an error code.

OUTPUT=$(${@:1} 2>&1)
if [ $? -eq 0 ]; then
    exit
fi

OLDLFS=$LFS
IFS=$'\n'
for l in $OUTPUT; do
    echo $l;
done
LFS=$OLDLFS