Add scripting section to docs

doc/075_scripting.rst

@@ -0,0 +1,39 @@
+..
+  Normally, there are no heading levels assigned to certain characters as the structure is
+  determined from the succession of headings. However, this convention is used in Python’s
+  Style Guide for documenting which you may follow:
+
+  # with overline, for parts
+  * for chapters
+  = for sections
+  - for subsections
+  ^ for subsubsections
+  " for paragraphs
+
+#########################
+Scripting
+#########################
+
+This is a list of how certain tasks may be accomplished when you use
+restic via scripts.
+
+Check if a repository is already initialized
+********************************************
+
+You may find a need to check if a repository is already initialized,
+perhaps to prevent your script from initializing a repository multiple
+times. The command ``snapshots`` may be used for this purpose:
+
+.. code-block:: console
+
+    $ restic -r /tmp/backup snapshots
+    Fatal: unable to open config file: Stat: stat /tmp/backup/config: no such file or directory
+    Is there a repository at the following location?
+    /tmp/backup
+
+If a repository does not exist, restic will return a non-zero exit code
+and print an error message. Note that restic will also return a non-zero
+exit code if a different error is encountered (e.g.: incorrect password
+to ``snapshots``) and it may print a different error message. If there
+are no errors, restic will return a zero exit code and print all the
+snapshots.

doc/index.rst

@@ -12,6 +12,7 @@ Restic Documentation
    050_restore
    060_forget
    070_encryption
+   075_scripting
    080_examples
    090_participating
    100_references