Hello,
While experimenting with inline environment variables, I noticed that
although they are correctly applied to command execution, their
expansion sometimes retains the previous value—but not always!
Context:
Bash version: GNU bash, version 5.2.21(1)-release (x86_64-pc-linux-gnu)
System locale: fr_FR.UTF-8 (floating-point numbers use a comma , as
the decimal separator)
Reproducing the issue:
Running the following script:
locale
echo
LC_ALL=C bash -c 'printf "%s %f\t%f\n" "$LC_NUMERIC" 3.141592654
3,141592654'
echo
LC_NUMERIC=C bash -c 'printf "%s %f\t%f\n" "$LC_NUMERIC" 3.141592654
3,141592654'
Produces this unexpected output:
LANG=fr_FR.UTF-8
LANGUAGE=fr_FR:fr_CA:en
LC_CTYPE="fr_FR.UTF-8"
LC_NUMERIC=fr_FR.UTF-8
LC_TIME=fr_FR.UTF-8
LC_COLLATE="fr_FR.UTF-8"
LC_MONETARY=fr_FR.UTF-8
LC_MESSAGES="fr_FR.UTF-8"
LC_PAPER=fr_FR.UTF-8
LC_NAME=fr_FR.UTF-8
LC_ADDRESS=fr_FR.UTF-8
LC_TELEPHONE=fr_FR.UTF-8
LC_MEASUREMENT=fr_FR.UTF-8
LC_IDENTIFICATION=fr_FR.UTF-8
LC_ALL=
bash: line 1: printf: 3,141592654: invalid number
fr_FR.UTF-8 3.141593 3.000000
bash: ligne 1 : printf: 3,141592654: nombre non valable
C 3.141593 3.000000
Observations:
In the first test (LC_ALL=C), the floating-point numbers are
correctly interpreted using a dot . as the decimal separator, but the
printed value of $LC_NUMERIC remains fr_FR.UTF-8 instead of C.
In the second test (LC_NUMERIC=C), the printed value correctly
reflects the inline environment assignment.
Additionally, there’s another strange behavior with inline environment
variables:
Running:
LANG=C LC_NUMERIC=C printf '%s\t%f\t%f\n' "$LC_NUMERIC" 3.141592654
3,141592654
Outputs:
bash: printf: 3,141592654: invalid number
fr_FR.UTF-8 3.141593 3.000000
Even though LC_NUMERIC=C is used to correctly parse 3.141592654, the
expansion of $LC_NUMERIC still prints its original value (fr_FR.UTF-8).
Conclusion:
This may not necessarily be a bug, but the behavior is counterintuitive
and inconsistent, making it difficult to predict how inline environment
variables will affect both variable expansion and command execution.
Some clarification in the Bash documentation could be helpful.
Any insights on this would be greatly appreciated!
Thanks,
--
Léa Gris
