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Specification

This file contains the complete godenv specification.

CHARACTER SET

All .env files MUST be in the UTF-8 encoding.

Syntax

COMMENTS

If the current line is started with a #, the line is interpreted as a comment. The <newline> character is excluded from the comment. Empty lines are ignored.

# Comment example. It starts from the '#' symbol and ends at the new line.

# ^ the empty line above is ignored.

NAME=VALUE

Any line <name>=<value> is treated as an environment variable assignment.

  • The expression at the left of the = symbol is the variable name.
  • The expression at the right of the = symbol is the variable value.

Whitespace characters ( , \t, etc.) on the left of the = symbol are restricted and lead to the scan error.

<name> is a token that MUST be composed of Unicode letters, Unicode digits, and the following characters: _ (underscore), , (comma), . (full stop), - (hyphen). The name MUST contain at least 1 character.

<value> is a UTF-8 string. It can be quoted or unquoted. Its interpretation slightly differs depending on the quotes used. The value MUST be a single-line string.

  • A value in single quotes. The value is a string between ' characters. Both quotation marks are excluded from the value.

    All characters inside a single-quoted value are treated as-is and are not escaped.

  • A value in double-quotes. The value is a string between " characters. Both quotation marks are excluded from the value.

    The special character sequences are escaped. E.g., \n is converted into <newline>.

  • An unquoted value string. The value is a string between = character and a <newline>. Both = and <newline> are excluded from the value.

    The special character sequences are escaped. E.g., \n is converted into <newline>.

# Valid variables
valid-name.with_special,symbols=value
КИРИЛЛИЦА_IS_SUPPRTED_AS_WELL=value
value_without_quotes=A value without quotes will be interpreted as a value.
value_with_single_quotes='A value between single quotation marks.'
value_with_double_quotes="A value between double quotation marks."

# The following names are implied illegal:
#  - this/name/contains/slashes
#  - LEGAL_NAME_BUT_WITH_SPACE =value

# The following values are implied illegal:
# 
# VALUE_WITHOUT_CLOSING_QUOTE="Illegal end of the line.
# 
# MULTI_LINE_VALUE="Multi line values
# are not supported yet"
#
# ILLEGAL_ESCAPE_SEQUENCE="\ <- this slash MUST be escaped as '\\'."

SPECIAL CASES

  • If a value is empty, it's interpreted as an empty string ''.
  • If a line lacks = character, the value is interpreted as an empty string ''.
  • If a file contains 2 or more identical <name>-s, then the last value is used.
# Value is an empty string ''
VARIABLE_WITH_EMPTY_VALUE=
# Value is an empty string '' 
VARIABLE_WITH_NO_EQUAL_CHAR

# Duplicated variables
VAR_NAME=value1
# The result is "value2" 
VAR_NAME=value2