Outputs git-big-picture to the “big-picture.svg” file every time something in a git repository changes.

update-big-picture-on-heads-change.sh

#!/bin/sh

# Uses ruby to encode JSON, watchman to watch for changes, git-big-picture to output the image.
# Can be improved by watching only file creation/deletion, since content changes are irrelevant.

CURRENT_PATH=`pwd`
JSON=`HEADS_PATH="$CURRENT_PATH/.git/logs/refs/heads" ruby -e "require 'json'; puts JSON.dump ENV['HEADS_PATH']"`

watchman -j <<-EOT
["watch", $JSON]
EOT

watchman -j <<-EOT
["trigger", $JSON, {
        "name": "big-picture",
        "append_files": false,
        "chdir": "../../../../",
        "command": ["git", "big-picture", "-o", "big-picture.svg"]
}]
EOT