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doc: fix locale range description

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Kay Marquardt (Gnadelwartz) 2021-01-04 15:39:01 +01:00
parent 8a095bc79f
commit 5f6476d691
1 changed files with 20 additions and 16 deletions
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doc/4_expert.md
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@ -9,13 +9,13 @@ two bytes for encoding and covers almost all `Latin` alphabets, also `Greek`, `C
`Hebrew`, `Arabic` and more. See [Wikipedia](https://en.wikipedia.org/wiki/UTF-8) for more details.
#### Setting up your Environment
In general `bash` and `GNU` utitities are UTF-8 aware if you to setup your environment
and your scripts accordingly:
In general `bash` and `GNU` utitities are UTF-8 aware aware if you to setup your environment
and your scripts accordingly (_locale setting_):
1. Your Terminal and Editor must support UTF-8:
Set Terminal and Editor locale to UTF-8, eg. in `Settings/Configuration` select UTF-8 (Unicode) as Charset.
2. Set `Shell` environment to UTF-8 in your `.profile` and your scripts. The usual settings are:
2. Set `Shell` locale environment to UTF-8 in your `.profile` and your scripts. The usual settings are:
```bash
export 'LC_ALL=C.UTF-8'
@ -31,18 +31,19 @@ export 'LANGUAGE=de_DE.UTF-8'
```bash
export 'LC_ALL=en_US.UTF-8'
export 'LANG=de_en_US.UTF-8'
export 'LANGUAGE=den_US.UTF-8'
export 'LANGUAGE=en_US.UTF-8'
```
3. make sure your bot scripts use the correct settings, eg. include the lines above at the beginning of your scripts
#### Known UTF-8 pitfalls
#### Known locale pitfalls
##### Missing locale C
Even required by POSIX standard some systems (e.g. Manjaro Linux) has no locale `C` and `C.UTF-8` installed.
If bashbot display a warning about missing locale you must install locale `C` and `C.UTF-8`.
If you don't know what locales are installed on your sytsem use `locale -a | more` to display them.
If you don't know what locales are installed on your sytsem use `locale -a` to display them.
[Gentoo Wiki](https://wiki.gentoo.org/wiki/UTF-8).
@ -51,22 +52,25 @@ If you don't know what locales are installed on your sytsem use `locale -a | mor
In ASCII times it was clear `[:lower:]` and `[a-z]` means ONLY the lowercase letters `[abcd...xyz]`.
With introdution of locales character classes and ranges contains every character fitting the class definition.
This mean `[:lower:]` and `[a-z]` contains ALL lowercase letters e.g. `ä á ø dž ȼ`
also, see [Unicode Latin lowercase letters]https://www.fileformat.info/info/unicode/category/Ll/list.htm)
This means for UTF-8 locales `[:lower:]` and `[a-z]` contains ALL lowercase letters, e.g. `á ø ü` also,
see [Unicode Latin lowercase letters](https://www.fileformat.info/info/unicode/category/Ll/list.htm)
If that's ok for your script your'e fine, but many scripts rely on the idea of ASCII ranges and may produce undesired results.
```bash
# try with different locales ...
lowercase="abcäöü"
# new bash to not change your current locale!
bash
lower="abcö"
[[ "$string" =~ ^[a-z]$ ] && echo "String is all lower case"
echo "$LC_ALL"
[[ "$lower" =~ ^[a-z]+$ ]] && echo "Ups, $lower is all lower case!" || echo "OK, not lower case"
LANG="en_EN
[[ "$string" =~ ^[a-z]$ ] && echo "String is all lower case"
LC_ALL="en_US.UTF-8"
[[ "$lower" =~ ^[a-z]+$ ]] && echo "Ups, $lower is all lower case!" || echo "OK, not lower case"
LANG="C"
[[ "$string" =~ ^[a-z]$ ] && echo "String is all lower case"
LC_ALL="C"
[[ "$lower" =~ ^[a-z]+$ ]] && echo "Ups, $lower is all lower case!" || echo "OK, not lower case"
```
There are three solutions:
@ -430,5 +434,5 @@ for every poll until the maximum of BASHBOT_SLEEP ms.
#### [Prev Advanced Use](3_advanced.md)
#### [Next Best Practice](5_practice.md)
#### $$VERSION$$ v1.21-4-g966ee5d
#### $$VERSION$$ v1.21-5-g8a095bc