bash.md: arrays & `unset`

1 files changed, 24 insertions, 6 deletions

diff --git a/bash.md b/bash.md
index aba50d5..ca3c722 100644
--- a/bash.md
+++ b/bash.md
@@ -1,12 +1,30 @@
 GNU `bash`
 ==========
 
-1. (Associative) arrays
-    * Yes:
+(Associative) arrays
+--------------------
 
-            func ${arr[@]+"${arr[@]}"}
+### Expansion
 
-    * No:
+Yes:
 
-            func "${arr[@]}"                # doesn't work with `nounset`
-            func "${arr[@]+"${arr[@]}"}"    # doesn't work with ('')
+    func ${arr[@]+"${arr[@]}"}
+
+No:
+
+    func "${arr[@]}"                # doesn't work with `nounset`
+    func "${arr[@]+"${arr[@]}"}"    # doesn't work with ('')
+
+### `unset`
+
+Yes:
+
+    unset -v 'arr[$i]'
+
+No:
+
+    unset -v arr[x]        # globbing
+    unset -v arr[$i]       # the same problem + quoting
+    unset -v 'arr["x"]'    # doesn't work for some reason
+    unset -v 'arr["]"]'    # the same as above; just to highlight the problem with funny characters in array indices
+                           # insightful discussion: https://lists.gnu.org/archive/html/help-bash/2016-09/msg00020.html