How to Convert the Space(s) to a Comma in a Linux File?

I want to convert the space(s) in a Linux file to a comma.

Problem

How to convert the space(s) to a comma in a Linux file?

Solution

For example, you have a test.txt file as shown in the image below:

Use the command below if you want to convert the space to a comma:

tr -s '[:blank:]' ',' < test.txt

So that your file will convert to the image below:

Not only that, the command can also be used if you have a file that has irregular spaces as shown in the image below:

Even the above command can also convert the free space created using the Tab key, as shown in the image below:

You can also use the below command in addition to the above command to make the space(s) in a Linux file a comma:

sed 's/\s\+/,/g' < test.txt

Note

If you want the free space to convert to something other than a comma, for example, to a colon (:), Then convert the comma in both commands above to become a colon as in the command below:

tr -s '[:blank:]' ':' < test.txt 

References

unix.stackexchange.com
stackoverflow.com