summaryrefslogtreecommitdiffstatshomepage
path: root/bash.md
blob: e1bd377feb1ca1cb436b20b093b14cdf86a127bb (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
GNU `bash`
==========

(Associative) arrays
--------------------

### Expansion

#### Do

    func ${arr[@]+"${arr[@]}"}

#### Don't

    func "${arr[@]}"                # Doesn't work with `nounset`.
    func "${arr[@]+"${arr[@]}"}"    # Doesn't work properly with `declare -a arr=('')`.

### `unset`

#### Do

    unset -v 'arr[x]'
    unset -v 'arr[$i]'

#### Don't

    unset -v arr[x]        # May break due to globbing.
    unset -v arr[$i]       # The same as above + possibly a pair of quotes is missing.
    unset -v 'arr["x"]'    # Doesn't work for some reason.
    unset -v 'arr["]"]'    # The same as above; just highlighting the problem with funny characters in array indices.
    # An insightful discussion: https://lists.gnu.org/archive/html/help-bash/2016-09/msg00020.html.