# Prefix stdout/stderr with a static prefix.
#
# e.g:
# $ static_prefix "[Hi there] " ls /
# [Hi there] bin
# [Hi there] boot
# ...
# [Hi there] vmlinuz

static_prefix() {
    local PREFIX
    local COMMAND

    PREFIX=$1
    COMMAND=${@:2}

    $COMMAND \
        1> >(sed >&1 "s#^#$PREFIX#") \
        2> >(sed >&2 "s#^#$PREFIX#")
}