From d4aec2c73cbf130f8c7ef174340eb959ca52fd7f Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Thu, 20 Feb 2025 12:25:43 -0800
Subject: cdalias: take zero, one or two args.

* cdlog.sh (cdlog.alias): Behave like cdlog.aliases in the
zero argument case, and in the one argument case list
the specified alias, if it exists.

* README.md: Updated. The cdaliases command becomes
deprecated.
---
 README.md | 14 +++++++++++---
 cdlog.sh  | 23 ++++++++++++++++++++---
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index 4857d22..b590d61 100644
--- a/README.md
+++ b/README.md
@@ -64,9 +64,7 @@ current again that new new session that `cdlog` had allocated on startup. That
 new session does not appear in the numbered list of recoverable sessions unless
 it has been already persisted by the execution of a directory-changing command.
 
-* The `cdalias` command is used for defining "cd aliases"; see below.
-
-* The `cdaliases` command lists cd aliases.
+* The `cdalias` command is used for defining or listing "cd aliases"; see below.
 
 * The `cdunalias` command removes a cd alias.
 
@@ -107,6 +105,16 @@ If the replacement begins with `@` then it is a search. If
 the search succeeds, then the result will be used as the alias
 value.
 
+When `cdalias` is invoked with no arguments, it lists all the
+currently defined aliases.
+
+When `cdalias` is invoked with one argument, and that argument
+names an alias, it lists that alias. Otherwise it fails
+with an error message.
+
+The deprecated `cdaliases` command also lists aliases; it
+will disappear in a future version of `cdlog`.
+
 ## Searches
 
 A search is an arguments which begins with `@`. The rest
diff --git a/cdlog.sh b/cdlog.sh
index fc8568f..feebfda 100644
--- a/cdlog.sh
+++ b/cdlog.sh
@@ -437,10 +437,27 @@ cdlog.alias()
 {
   local def=
 
-  if [ $# -ne 2 ] ; then
-    printf "cdlog.alias: two arguments required\n"
+  case $# in
+  ( 0 )
+    cdlog.aliases
+    return $?
+    ;;
+  ( 1 )
+    if [ ${cdlog_alias[$1]+y} ] ; then
+      printf "%s -> %s\n" "$1" "${cdlog_alias[$1]}"
+      return 0
+    else
+      printf "cdlog.alias; %s: not defined\n" "$1"
+      return 1
+    fi
+    ;;
+  ( 2 )
+    ;;
+  ( * )
+    printf "cdlog.alias: one or two arguments required\n"
     return 1
-  fi
+    ;;
+  esac
 
   if [ -z "$1" ] ; then
     printf "cdlog.alias: alias may not be empty\n"
-- 
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