;doc: cli, ui, web: mention/link to shell completions

hledger-ui/hledger-ui.m4.md

@@ -77,6 +77,9 @@ _generaloptions_
 
 With hledger-ui, the `--debug` option sends debug output to a `hledger-ui.log` file in the current directory.
 
+If you use the bash shell, you can auto-complete flags by pressing TAB in the command line.
+If this is not working see [Install > Shell completions](install.html#shell-completions).
+
 # MOUSE
 
 In most modern terminals, you can navigate through the screens with a

hledger-web/hledger-web.m4.md

@@ -131,6 +131,9 @@ Reporting options and/or query arguments can be used to set an initial query,
 which although not shown in the UI, will restrict the data shown
 (in addition to any search query entered in the UI).
 
+If you use the bash shell, you can auto-complete flags by pressing TAB in the command line.
+If this is not working see [Install > Shell completions](install.html#shell-completions).
+
 # PERMISSIONS
 
 By default, hledger-web allows anyone who can reach it to view the journal

hledger/hledger.m4.md

@@ -579,6 +579,14 @@ If you need that, you can do it in the shebang line instead. Eg:
 
 The config file feature has been added in hledger 1.40 and is considered *experimental*.
 
+## Shell completions
+
+If you use the bash shell, you can optionally set up context-sensitive autocompletions when you press TAB in a hledger command line.
+At a bash shell prompt, try pressing
+`hledger<SPACE><TAB><TAB>` (should list all hledger commands)
+or `hledger reg acct:<TAB><TAB>` (should list your top-level account names).
+If completions aren't working, or for more details, see [Install > Shell completions](install.html#shell-completions).
+
 # Output
 
 ## Output destination