1

## Generate updated output file from given command's stdout:

     2

#

     3

#   do_update $out $BIN/cmd --args

     4

#

     5

# Writes output to a temporary .new file, optionally shows a diff of changes, and commits

     6

# the new version to $out (unless noop'd).

     7

function apply_cmd {

     8

    local out="$1"

     9

    local tmp="$out.new"

    10

    11

    debug "$out"

    12

    cmd "${@:2}" > "$tmp"

    13

    14

    # compare

    15

    if [ -e "$out" -a -n "$APPLY_DIFF" ]; then

    16

        debug "  changes:"

    17

    18

        # terse

    19

        cmd_indent "        " diff --unified=1 "$out" "$tmp" || true

    20

    fi

    21

    22

    # deploy

    23

    if [ "$APPLY" = 0 ]; then

    24

        # cleanup

    25

        debug "  no-op"

    26

    27

        cmd rm "$tmp"

    28

    else

    29

        # commit

    30

        debug "  apply"

    31

    32

        cmd mv "$tmp" "$out"

    33

    fi

    34

}

    35