Simplify config handling

* Switch to urfave/cli/v2
* Add more environment variables

README.md

@@ -597,35 +597,33 @@ $ cp mark /usr/local/bin
 
 ## Usage
 
-```
-mark [options] [-u <username>] [-p <password>] [-k] [-l <url>] -f <file>
-mark [options] [-u <username>] [-p <password>] [-k] [-b <url>] -f <file>
-mark [options] [-u <username>] [-p <password>] [--drop-h1] -f <file>
-mark -v | --version
-mark -h | --help
 ```
 
-- `-u <username>` — Use specified username for updating Confluence page.
-- `-p <password>` — Use specified password for updating Confluence page.
-    Specify `-` as password to read password from stdin.
-- `-l <url>` — Edit specified Confluence page.
-    If -l is not specified, file should contain metadata (see above).
-- `-b <url>` or `--base-url <url>` – Base URL for Confluence.
-    Alternative option for `base_url` config field.
-- `-f <file>` — Use specified markdown file(s) for converting to html. Supports file globbing patterns (needs to be quoted).
-- `-c <path>` or `--config <path>` — Specify a path to the configuration file.
-- `-k` — Lock page editing to current user only to prevent accidental
-    manual edits over Confluence Web UI.
-- `--space <space>` - Use specified space key. If the space key is not specified, it must be set in the page metadata.
-- `--drop-h1` – Don't include H1 headings in Confluence output.
-  This option corresponds to the `h1_drop` setting in the configuration file.
-- `--title-from-h1` - Extract page title from a leading H1 heading. If no H1 heading on a page exists, then title must be set in the page metadata.
-  This option corresponds to the `h1_title` setting in the configuration file.
-- `--dry-run` — Show resulting HTML and don't update Confluence page content.
-- `--minor-edit` — Don't send notifications while updating Confluence page.
-- `--trace` — Enable trace logs.
-- `-v | --version` — Show version.
-- `-h | --help` — Show help screen and call 911.
+USAGE:
+   mark [global options] [arguments...]
+
+GLOBAL OPTIONS:
+   --files value, -f value       use specified markdown file(s) for converting to html. Supports file globbing patterns (needs to be quoted). [$MARK_FILES]
+   --compile-only                show resulting HTML and don't update Confluence page content. (default: false) [$MARK_COMPILE_ONLY]
+   --dry-run                     resolve page and ancestry, show resulting HTML and exit. (default: false) [$MARK_DRY_RUN]
+   --edit-lock, -k               lock page editing to current user only to prevent accidental manual edits over Confluence Web UI. (default: false) [$MARK_EDIT_LOCK]
+   --drop-h1                     don't include H1 headings in Confluence output. (default: false) [$MARK_H1_DROP]
+   --title-from-h1               extract page title from a leading H1 heading. If no H1 heading on a page exists, then title must be set in the page metadata. (default: false) [$MARK_H1_TITLE]
+   --minor-edit                  don't send notifications while updating Confluence page. (default: false) [$MARK_MINOR_EDIT]
+   --color value                 display logs in color. Possible values: auto, never. (default: "auto") [$MARK_COLOR]
+   --debug                       enable debug logs. (default: false) [$MARK_DEBUG]
+   --trace                       enable trace logs. (default: false) [$MARK_TRACE]
+   --username value, -u value    use specified username for updating Confluence page. [$MARK_USERNAME]
+   --password value, -p value    use specified token for updating Confluence page. Specify - as password to read password from stdin, or your Personal access token. Username is not mandatory if personal access token is provided. For more info please see: https://developer.atlassian.com/server/confluence/confluence-server-rest-api/#authentication. [$MARK_PASSWORD]
+   --target-url value, -l value  edit specified Confluence page. If -l is not specified, file should contain metadata (see above). [$MARK_TARGET_URL]
+   --base-url value, -b value    base URL for Confluence. Alternative option for base_url config field. [$MARK_BASE_URL]
+   --config value, -c value      use the specified configuration file. (default: "/home/mruger/.config/mark") [$MARK_CONFIG]
+   --ci                          run on CI mode. It won't fail if files are not found. (default: false) [$MARK_CI]
+   --space value                 use specified space key. If the space key is not specified, it must be set in the page metadata. [$MARK_SPACE]
+   --help, -h                    show help
+   --version, -v                 print the version
+
+```
 
 You can store user credentials in the configuration file, which should be
 located in ~/.config/mark (or specified via `-c --config <path>`) with the following format (TOML):
@@ -634,9 +632,9 @@ located in ~/.config/mark (or specified via `-c --config <path>`) with the follo
 username = "your-email"
 password = "password-or-api-key-for-confluence-cloud"
 # If you are using Confluence Cloud add the /wiki suffix to base_url
-base_url = "http://confluence.local"
-h1_title = true
-h1_drop = true
+base-url = "http://confluence.local"
+h1-title = true
+h1-drop = true
 ```
 
 **NOTE**: Labels aren't supported when using `minor-edit`!