Update README

shell-completion/README.md

@@ -15,8 +15,8 @@ The completions can handle hledger's CLI:
 
 - commands and generic options
 - command-specific options
-- filenames for options that take a filename as argument
-- account names from journal files (but not yet for files named by `--file`)
+- most option arguments
+- account names, tags, payees, etc. from journal files
 - query filter keywords like `status:`, `tag:`, or `amt:`
 
 Installation for end users
@@ -27,22 +27,45 @@ Completions are currently only implemented for the Bash shell.
 Please check first if the completions for hledger are already installed on your
 distribution. Refer to the last paragraph of this section for how to test that.
 
-To install the completions manually, follow this steps:
+To install from the repository, do:
 
-- Download or copy the file `shell-completion/hledger-completion.bash` and save
-  it as `~/.hledger-completion.bash`.
+``` sh
+cd /path-to-repo/shell-completion
+make install
+```
 
-- Add the command `source ~/.hledger-completion.bash` this to the end of your
-  `~/.bashrc` file.
+Completions installed this way will be loaded dynamically after you use the hledger
+command. Upon the first invocation of a command that has no predefined completion
+bash looks for a file with the same name in a set of predefined locations in this order:
 
-- Then, you have to start a new Bash, e.g. by typing `bash` on the current
-  shell.
+- $BASH_COMPLETION_USER_DIR/completions
+- $XDG_DATA_HOME/bash-completion/completions
+- $HOME/.local/share/bash-completion/completions
+- etc.
 
-Example installation script:
+You can manually achieve the effects of `make install` by copying
+`shell-completion/hledger-completion.bash` to one of the above, and renaming it
+to `hledger`, `_hledger` or `hledger.bash`. For the gory details, type this in a
+bash shell:
+
+``` sh
+type __load_completion
+```
+
+To install the completions manually, you can also just download and copy
+`shell-completion/hledger-completion.bash` to a directory of your choosing, and
+source it from your shell start up files. This way completions are loaded
+eagerly and that adds a delay to shell start up time.
+
+Example:
 
 ```
-cp hledger-completion.bash ~/.hledger-completion.bash
-echo 'source ~/.hledger-completion.bash' >> ~/.bashrc
+cp hledger-completion.bash ~/.bash_completion.d/hledger
+echo 'source ~/.bash_completion.d/hledger' >> ~/.bashrc
+# Restart shell
+exec bash
+# Confirm that completion is loaded
+complete -p hledger
 ```
 
 Now, try it by typing `hledger` (with a space after the command) and press the