LPIC-1 107.3 — Localisation and Internationalisation

Exam weight: 3 — LPIC-1 v5, Exam 102

What You Need to Know

From the official LPIC-1 objectives:

• Configure locale settings and environment variables.
• Configure timezone settings and environment variables.

Key files and commands: /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.

Time Zones

Time zones are regions of Earth that share the same local time, defined as an offset from UTC (Coordinated Universal Time). The term GMT (Greenwich Mean Time) is used as a synonym for UTC in offset-based names.

• GMT-5 means the region is 5 hours behind UTC.
• GMT+3 means UTC time is 3 hours behind — the region is 3 hours ahead.

Servers and cloud services commonly run with the hardware clock set to UTC, leaving time zone adjustments to individual users.

Checking the Current Time Zone

$ date
Mon Oct 21 10:45:21 -03 2019

The -03 offset shows the system is 3 hours behind UTC (GMT-3 zone).

$ timedatectl
               Local time: Sat 2019-10-19 17:53:18 -03
           Universal time: Sat 2019-10-19 20:53:18 UTC
                 RTC time: Sat 2019-10-19 20:53:18
                Time zone: America/Sao_Paulo (-03, -0300)
System clock synchronized: yes

timedatectl is available on systems with systemd.

System Time Zone Files

Generic UTC-offset names must include Etc, for example Etc/GMT+3 (not just GMT+3).

$ cat /etc/timezone
America/Sao_Paulo

/etc/localtime points to /usr/share/zoneinfo/America/Sao_Paulo.

tzselect — Interactive Zone Finder

tzselect guides you through continent, country, and region menus to identify the correct zone name. It does not change system settings — it outputs the TZ value for you to use:

$ tzselect
# ... interactive menu ...
# Result:
TZ='America/Sao_Paulo'; export TZ

Add that line to ~/.profile to make it permanent for your sessions.

TZ Environment Variable

TZ overrides the system time zone for the current shell session without changing system files:

$ env TZ='Africa/Cairo' date
Mon Oct 21 15:45:21 EET 2019

Language and Character Encoding

LANG Variable

LANG is the primary locale variable. Its format is language_REGION.ENCODING, for example pt_BR.UTF-8 (Brazilian Portuguese, UTF-8) or en_US.UTF-8.

$ echo $LANG
pt_BR.UTF-8

System-wide default is set in /etc/locale.conf:

$ cat /etc/locale.conf
LANG=pt_BR.UTF-8

Change it with localectl on systemd systems:

localectl set-locale LANG=en_US.UTF-8

To override for the current session, export LANG or LC_ALL.

LC_* Variables

These variables control specific locale aspects and override LANG for their category:

$ locale
LANG=pt_BR.UTF-8
LC_CTYPE="pt_BR.UTF-8"
LC_NUMERIC=pt_BR.UTF-8
...
LC_ALL=

LC_ALL is empty by default. Setting it to en_US.UTF-8 temporarily forces English locale for all aspects:

$ env LC_ALL=en_US.UTF-8 date
Mon Oct 21 10:45:21 -03 2019

For shell scripts, set LANG=C to avoid locale-dependent behavior in sorting and character comparisons.

Character Encoding

iconv — Encoding Conversion

iconv converts a file from one character encoding to another:

iconv -f ISO-8859-1 -t UTF-8 original.txt > converted.txt

Add //TRANSLIT to the target encoding to transliterate characters that don’t exist in the target charset:

iconv -f UTF-8 -t ASCII//TRANSLIT -o ascii.txt readme.txt

Quick Reference

Time zone files:
  /etc/timezone          zone name (e.g., America/Sao_Paulo, Etc/GMT+3)
  /etc/localtime         symlink to /usr/share/zoneinfo/<zone>
  /usr/share/zoneinfo/   zone data files

Time zone commands:
  date                   current time + UTC offset
  timedatectl            detailed time/zone info (systemd)
  tzselect               interactive zone finder (outputs TZ value)
  TZ='Zone/Name'         per-session override; add to ~/.profile to persist

Locale settings:
  LANG=language_REGION.ENCODING   primary locale (e.g., en_US.UTF-8)
  LC_ALL                  overrides all LC_* and LANG
  LC_COLLATE              sort / alphabetical order
  LC_CTYPE                character types (upper/lower)
  LC_MESSAGES             program message language
  LC_MONETARY             currency format
  LC_NUMERIC              decimal / thousand separator
  LC_TIME                 date/time format

Locale commands:
  locale                  show all current LC_* values
  localectl set-locale LANG=en_US.UTF-8   (systemd)

Locale files:
  /etc/locale.conf        system-wide locale settings

Character encodings:
  ASCII       7-bit, English only
  ISO-8859    8-bit family, extends ASCII
  Unicode     universal standard
  UTF-8       variable-width Unicode, ASCII-compatible, Linux default

iconv:
  iconv -f SRC -t DST input.txt > output.txt
  iconv -f SRC -t DST//TRANSLIT -o out.txt in.txt
  iconv -l                list all encodings

Exam Questions

1. What file stores the system default time zone name? → /etc/timezone
2. What is /etc/localtime? → A symlink to the active zone data file in /usr/share/zoneinfo/.
3. Where are all time zone data files stored? → /usr/share/zoneinfo/
4. What does tzselect do? → Interactively guides the user to identify their time zone and outputs the TZ value; does not change system settings.
5. What command shows the current time zone with full systemd details? → timedatectl
6. How do you temporarily run a command in a different time zone? → env TZ='Zone/Name' command
7. What is the format of the LANG variable? → language_REGION.ENCODING, e.g., en_US.UTF-8
8. What does LC_ALL do? → Overrides all other LC_* variables and LANG.
9. Which LC_* variable controls the decimal and thousand separator? → LC_NUMERIC
10. Which LC_* variable controls alphabetical sorting? → LC_COLLATE
11. What file stores system-wide locale settings? → /etc/locale.conf
12. What command changes the system locale on a systemd system? → localectl set-locale LANG=en_US.UTF-8
13. What is UTF-8? → A variable-width Unicode encoding, backward-compatible with ASCII, default on modern Linux.
14. What command converts a file from ISO-8859-1 to UTF-8? → iconv -f ISO-8859-1 -t UTF-8 input.txt > output.txt
15. What does //TRANSLIT do in iconv? → Transliterates characters that do not exist in the target encoding instead of replacing them with ?.
16. How do you list all encodings supported by iconv? → iconv -l or iconv --list
17. What is the Etc/GMT+3 time zone? → A zone where the offset from UTC is +3 hours (generic UTC-offset names must use the Etc/ prefix).
18. Why is LANG=C recommended in shell scripts? → The C locale provides unambiguous, locale-independent behavior for sorting and character comparisons.

Exercises

Exercise 1 — Reading the Time Zone from date

The date command outputs: Mon Oct 21 18:45:21 +05 2019. What is the time zone in Etc/ notation?

Exercise 2 — Setting /etc/localtime

To make Europe/Brussels the system default time zone, what should /etc/localtime point to?

Exercise 3 — iconv Conversion

Convert the WINDOWS-1252 encoded file old.txt to UTF-8 and save it as new.txt.

iconv -f WINDOWS-1252 -t UTF-8 -o new.txt old.txt

Exercise 4 — Per-Session Time Zone

Make Pacific/Auckland the default time zone for the current shell session only.

export TZ=Pacific/Auckland

Exercise 5 — Transliteration with iconv

Convert the UTF-8 file readme.txt to a plain ASCII file ascii.txt, keeping characters as readable as possible by transliterating non-ASCII characters.

iconv -f UTF-8 -t ASCII//TRANSLIT -o ascii.txt readme.txt

LPIC-1 Study Notes | Topic 107: Administrative Tasks