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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
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