26

I use the Italian localization of Cygwin, and therefore my printf command uses commas to separate floats, and won't understand dot-separated floats

$ printf "%f" 3.1415 -bash: printf: 3.1415: invalid number 0,000000 $ printf "%f" 3,1415 3,141500

This gives rise to several problems because basically everything else uses a dot to separate decimal digits.

How can I change the decimal separator from comma to dot?

Improve this question

3 Answers 3

Reset to default
31

There are several local variables that control the localization of Cygwin (or of any bash shell, for that matter). You can see them along with their value using the locale command. You should see something like this:

$ locale LANG=it_IT.UTF-8 LC_CTYPE="it_IT.UTF-8" LC_NUMERIC="it_IT.UTF-8" LC_TIME="it_IT.UTF-8" LC_COLLATE="it_IT.UTF-8" LC_MONETARY="it_IT.UTF-8" LC_MESSAGES="it_IT.UTF-8" LC_ALL=

You can see the possible values of the variables by using locale -va. They are all formatted like <language>_<nation>.UTF-8. The UTF-8 part is optional.

In order to switch to "North American" float separation style, simply set LC_NUMERIC to its American value:

$ export LC_NUMERIC="en_US.UTF-8"

Simply setting the variable LC_NUMERIC as if it were a regular variable won't work. You need to use the export command.

You can put this in the header of your scripts, or you can make it permanent by adding it to your ~/.bashrc or your ~/.bash_profile file.

Hope this was helpful!

Improve this answer
Sign up to request clarification or add additional context in comments.

3 Comments

You could just set LC_NUMERIC="en_US.UTF-8", but that does not change the setting in the whole system, but in the scope of the script or the shell the setting is done in. Besides, you could change the locale just for the command by LC_NUMERIC="en_US.UTF-8" printf "%f" 3.1415.
See answer below for a better (IMO) solution that works independently of locales that you have installed.
For more on what export is, and when and how to use it, see my answer here: stackoverflow.com/a/62626515/4561887.
14

If you don't want to mess with system configuration, you can respect your locale but make sure your script uses dots for decimals with:

$ printf "%f" 3.5 -bash: printf: 3,5: invalid number 0.000000 $ LANG=C printf "%f" 3.5 3.500000
Improve this answer

1 Comment

There are cases where LANG=C is not enough, LC_NUMERIC=C works better.
4

Use:

$ VAR=3,1415 $ echo ${VAR/,/.} 3.1415

or

$ VAR=${VAR/,/.} $ echo $VAR 3.1415

Another example:

VAR=$(echo "scale=1; $NUMBER/60" | bc) VAR=${VAR/./,} $ VAR=$(echo "scale=1; 150/60" | bc);echo $VAR 2.5 $ VAR=$(echo "scale=1; 150/60" | bc); VAR=${VAR/./,};echo $VAR 2,5
Improve this answer

1 Comment

Welcome to Stack Overflow! While this code may solve the question, including an explanation of how and why this solves the problem would really help to improve the quality of your post, and probably result in more up-votes. Remember that you are answering the question for readers in the future, not just the person asking now. Please edit your answer to add explanations and give an indication of what limitations and assumptions apply.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.