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107-3-Localisation-and-internationalisation
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107-3-Localisation-and-internationalisation
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####################################################################
107.3 Localisation and internationalisation
####################################################################
Candidates should be able to localise a system in a different language than English. As well, an understanding of why LANG=C is useful when scripting.
Key Knowledge Areas
& Configure locale settings and environment variables.
& Configure timezone settings and environment variables.
################################
Terms and Utilities
################################
& /etc/timezone
& /etc/localtime
& /usr/share/zoneinfo/
& LC_*
& LC_ALL
& LANG
& TZ
& /usr/bin/locale
& tzselect
& timedatectl
& date
& iconv
& UTF-8
& ISO-8859
& ASCII
& Unicode
################################
timezone
################################
On linux systems you can use date and cal commands to check the date and the calendar. It is possible to print a custom date using + formatter:
[mojtaba@funlife ~]$ date +'%Y%m%d-%M'
20160103-39
[mojtaba@funlife ~]$ date +'%Y%m%d-%H%M'
20160103-2239
Timezone determines what is your time difference comparing with a reference timezone. This way you can talk about times regardless from your location. In another words, I can tell you "start the change request at 02:30 UTC" we both know when the change will be started in our own timezone (mine is 02:30 minus 3:30).
You can configure your timezone while installing the system or by using a GUI in the system settings. It is even possible to set the timezone by clicking or right-clicking on the date and time on your panel. But as always there is a command line way. The old one used to be tzconfig but it is not used anymore.
Different distros do have their own configuration commands, a general one is:
tzselect
Please identify a location so that time zone rules can be set correctly.
Please select a continent, ocean, "coord", or "TZ".
1) Africa
2) Americas
3) Antarctica
4) Arctic Ocean
5) Asia
6) Atlantic Ocean
7) Australia
8) Europe
9) Indian Ocean
10) Pacific Ocean
11) coord - I want to use geographical coordinates.
12) TZ - I want to specify the time zone using the Posix TZ format.
This process will suggest you to set a variable called TZ as follow to set your own time zone, but not the systems:
TZ='Asia/Tehran'; export TZ
################################
Configuring timezone
################################
There is a directory at /usr/share/zoneinfo/ containing all the timezone info. These are binary files. If you need to change your systems timezone you need to change 2 files:
cat /etc/timezone
Asia/Tehran
and there is a short link at this place:
# ls -ltrh /etc/localtime
-rw-r--r-- 1 root root 1.7K Jan 2 18:10 /etc/localtime
This file should be replaced by the correct file from /usr/share/zoneinfo/. It is nicer to make a symbolic link rather than copying the actual file. This will prevent the conflicts during next upgrades.
################################
Configuring Languages
################################
You can check the status of current selected system language by issuing locale:
$locale
LANG=en_US.UTF-8
LANGUAGE=
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=
These are all environment variables telling system what languages to use. Here I'm using LANG=en_US.UTF-8 which means I'm using English with US variant and UTF-8 encoding.
UTF-8 and other encodings will be discussed a bit later in this chapter
Other variables tell the system how to show different things based on localisation systems. For example if we change the LC_TIME to "en_GB.UTF-8" the time will be printed in Great Britain format from that moment on.
Another important settings is LC_ALL. It can be used to change ALL settings. If you do a export LC_ALL=fa_IR.UTF-8, all the settings will be set to that one, with no exception. It is always possible to unset LC_ALL.
################################
LANG=C
################################
Another important point to know is the LANG=C settings. This indicates two things:
1-All language settings will be default (en.US)
2-Binary sort order
It is also possible to do a LC_ALL=C.
################################
changing or adding locales
################################
This is not a part of LPIC exam but it is good to know that on a debian based machine, you can change, add or set your default locales using dpkg-reconfigure locales.
################################
Character Encoding
################################
################################
ACSII
################################
Computers used to work with 7bit characters encoding. That would give us 128 characters which was enough for numbers, punctuation and digits!
################################
ISO-8859
################################
It had more characters and a lots of sets for Thai, Arabic and other languages but still had ASCII character sets.
################################
UTF-8
################################
The Unicode Transformation Format is the newest encoding method. It is a real universal encoding with characters not only for all written languages but also for fun characters like ¾, ♠, π and ⚤. It is backward compatible with the ASCII and uses 8 bit code units (not 8 bit coding!). In most cases it is a good idea to use UTF-8 and be sure that your system will work in practically all cases.
################################
iconv
################################
If you needed to convert coding to each other, the command is iconv. The -l switch will show you all the available codings:
iconv -f WINDOWS-1258 -t UTF-8 /tmp/myfile.txt
Note: -f is for "from" and -t is for "to". Easy to remember
In 2016 you will seldom need this command but it is a must to know it, specially if you are living in a non US country!