sed行删除不必要的空格也是删除行尾和其他奇怪的新行问题

Question

I have to deal with an output from a command. Just plain text. What I want is to remove unnecessary spaces by using

sed 's/  */ /g'

But it's doing it wrong - it seems to remove new line characters as well...

The other problem is about the $ character representing the 'new line'.

When I'm writing sth like this:

sed 's/$/FOO/g'

It is really replacing all the new line chars with the word FOO. So its basically like:

text
text
text

Is converted to

textFOOtextFOOtext

The problem starts when 2 new lines occur. The text:

text

text

Is converted to:

textFOOFOOtext

BUT -- absolutely no SED line is able to convert the 2 new lines into one. I tried everything I found on the web.

How do I remove that additional new line?

Answer 1

Check if this helps:

tr -s ' ' < File

This will change multiple spaces to single space, if thats what u want