Hello

I would like to trim any trailing spaces from a field before it is written to a file.

Here is an example of the output string:
Index ~Description~Keys ~Time ~

There can be any number of trailing spaces before the tilde

I tried to use sed, and it sort of worked - it got rid of the trailing spaces but, it also removed the space between the words in the Description, which I don't want.

Here is the sed command I used
sed -e 's/[ ]*//g' file1 > file2

How can I modify this to delete the trailing spaces but keep the spaces between words?

Any help would be greatly appreciated - Thanks!

Try:
tr -s ' ' < input_file > output_file

Please note there is 1 (one) space between the single quotes.

If you need to remove only spaces before tilde this one should work:

sed 's/[ ]*~/~/g' file1 >file2

sed 's/^[[:space:]]*\(.*\)[[:space:]]*$/\1/'