The locale command is an essential Linux utility that displays and manages locale-specific information on your system. Locales define how programs should handle language-specific conventions such as date formats, currency symbols, number representations, and character encoding. Understanding and properly configuring locales is crucial for system administrators and developers working in multilingual environments.
What is Locale in Linux?
A locale is a set of parameters that defines the user’s language, country, and character encoding preferences. It determines how applications display dates, times, numbers, currency, and other region-specific information. Linux uses the GNU C Library (glibc) locale system, which follows the POSIX standard for internationalization.
Each locale consists of several categories:
- LC_COLLATE: Defines alphabetical ordering rules
- LC_CTYPE: Character classification and case conversion
- LC_MESSAGES: Language for system messages
- LC_MONETARY: Currency formatting
- LC_NUMERIC: Number formatting
- LC_TIME: Date and time formatting
Basic locale Command Syntax
The basic syntax of the locale command is:
locale [OPTION]... [NAME]...When used without any options, locale displays the current locale settings for all categories.
Displaying Current Locale Settings
To view your current locale configuration, simply run:
$ localeThis command produces output similar to:
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=Each line shows a locale category and its current value. The format follows the pattern: language_COUNTRY.encoding
Common locale Command Options
1. List All Available Locales (-a)
To see all locales installed on your system:
$ locale -aSample output:
C
C.UTF-8
POSIX
en_AG
en_AG.utf8
en_AU.utf8
en_BW.utf8
en_CA.utf8
en_DK.utf8
en_GB.utf8
en_HK.utf8
en_IE.utf8
en_IN
en_IN.utf8
en_NG
en_NG.utf8
en_NZ.utf8
en_PH.utf8
en_SG.utf8
en_US.utf8
en_ZA.utf8
en_ZM
en_ZW.utf82. Display Specific Category Information (-c)
To view information about a specific locale category:
$ locale -c LC_TIMEThis shows detailed information about time formatting rules for the current locale.
3. Get Keyword Information (-k)
To display locale data with keyword names:
$ locale -k LC_MONETARYExample output:
int_curr_symbol="USD "
currency_symbol="$"
mon_decimal_point="."
mon_thousands_sep=","
mon_grouping=3;3
positive_sign=""
negative_sign="-"
int_frac_digits=2
frac_digits=2
p_cs_precedes=1
p_sep_by_space=0
n_cs_precedes=1
n_sep_by_space=0
p_sign_posn=1
n_sign_posn=14. Show Character Maps and Locales (-m)
To list all available character maps:
$ locale -mThis displays character encoding maps like UTF-8, ISO-8859-1, etc.
Working with Specific Locale Categories
Examining LC_TIME Category
To see detailed time formatting information:
$ locale LC_TIMEOutput shows:
Sun;Mon;Tue;Wed;Thu;Fri;Sat
Sunday;Monday;Tuesday;Wednesday;Thursday;Friday;Saturday
Jan;Feb;Mar;Apr;May;Jun;Jul;Aug;Sep;Oct;Nov;Dec
January;February;March;April;May;June;July;August;September;October;November;December
AM;PM
%a %b %e %H:%M:%S %Z %Y
%m/%d/%Y
%H:%M:%S
%I:%M:%S %pExamining LC_NUMERIC Category
To view number formatting rules:
$ locale -k LC_NUMERICSample output:
decimal_point="."
thousands_sep=","
grouping=3;3Setting and Changing Locales
Temporary Locale Changes
You can temporarily change the locale for a single command:
$ LC_TIME=de_DE.UTF-8 dateThis displays the date in German format while keeping other locale settings unchanged.
Setting LANG Environment Variable
To change the default locale for the current session:
$ export LANG=fr_FR.UTF-8
$ localeThis sets French as the default locale for all categories not explicitly set.
Using LC_ALL for Complete Override
To override all locale categories at once:
$ export LC_ALL=es_ES.UTF-8
$ localeThe LC_ALL variable takes precedence over all other locale settings.
Practical Examples and Use Cases
Example 1: Checking Date Format Across Locales
Compare date formats in different locales:
$ date
Mon Aug 25 07:19:15 IST 2025
$ LC_TIME=de_DE.UTF-8 date
Mo 25. Aug 07:19:15 IST 2025
$ LC_TIME=ja_JP.UTF-8 date
2025年 8月25日 月曜日 07:19:15 ISTExample 2: Number Formatting Differences
See how numbers are formatted in different locales:
$ printf "%'.2f\n" 1234567.89
1,234,567.89
$ LC_NUMERIC=de_DE.UTF-8 printf "%'.2f\n" 1234567.89
1.234.567,89
$ LC_NUMERIC=fr_FR.UTF-8 printf "%'.2f\n" 1234567.89
1 234 567,89Example 3: Currency Display
Check currency formatting across locales:
$ locale -k LC_MONETARY | grep currency_symbol
currency_symbol="$"
$ LC_MONETARY=en_GB.UTF-8 locale -k LC_MONETARY | grep currency_symbol
currency_symbol="£"
$ LC_MONETARY=ja_JP.UTF-8 locale -k LC_MONETARY | grep currency_symbol
currency_symbol="¥"Troubleshooting Common Locale Issues
Missing Locale Error
If you encounter “locale: Cannot set LC_* to default locale” errors:
$ sudo locale-gen en_US.UTF-8
$ sudo update-locale LANG=en_US.UTF-8Checking Locale Generation Status
Verify if a specific locale is installed:
$ locale -a | grep en_US
en_US.utf8Installing Additional Locales
On Ubuntu/Debian systems:
$ sudo apt-get install language-pack-de
$ sudo locale-gen de_DE.UTF-8Advanced locale Command Usage
Displaying Character Classification
To see character classification rules:
$ locale -k LC_CTYPE | head -10This shows how characters are classified (uppercase, lowercase, digits, etc.) in the current locale.
Comparing Locales
Compare sorting rules between locales:
$ echo -e "ä\na\nz" | sort
a
z
ä
$ echo -e "ä\na\nz" | LC_COLLATE=de_DE.UTF-8 sort
a
ä
zBest Practices for Locale Management
1. System-wide Configuration
Edit /etc/locale.conf for system-wide settings:
LANG=en_US.UTF-8
LC_TIME=en_GB.UTF-82. User-specific Configuration
Add locale settings to ~/.bashrc or ~/.profile:
export LANG=en_US.UTF-8
export LC_TIME=en_GB.UTF-83. Application-specific Locales
Use environment variables for specific applications:
LC_MONETARY=en_GB.UTF-8 your_applicationIntegration with Programming
Shell Scripting
Check locale in scripts:
#!/bin/bash
if [[ "$LANG" == *"UTF-8"* ]]; then
echo "UTF-8 encoding detected"
else
echo "Non-UTF-8 encoding: $LANG"
fiBackup Current Locale
Save current locale settings:
$ locale > locale_backup.txtSecurity Considerations
When working with locales in production environments:
- Always validate locale input from external sources
- Use UTF-8 encoding when possible for better security
- Be aware that locale settings can affect string comparisons and sorting
- Test applications with different locales to prevent unexpected behavior
Conclusion
The locale command is a powerful tool for managing internationalization and localization settings in Linux systems. Understanding how to display, configure, and troubleshoot locale settings is essential for system administrators and developers working in multilingual environments. By mastering the various options and use cases covered in this guide, you’ll be well-equipped to handle locale-related tasks efficiently and effectively.
Regular monitoring of locale settings ensures applications behave correctly across different languages and regions, making your Linux systems more accessible and user-friendly for international audiences.
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- What is Locale in Linux?
- Basic locale Command Syntax
- Displaying Current Locale Settings
- Common locale Command Options
- Working with Specific Locale Categories
- Setting and Changing Locales
- Practical Examples and Use Cases
- Troubleshooting Common Locale Issues
- Advanced locale Command Usage
- Best Practices for Locale Management
- Integration with Programming
- Security Considerations
- Conclusion
