sed newline to tab ,problem

Shell Programming and Scripting
1

Input:

gstreamer-plugins-good
gstreamer-plugins-bad 
gstreamer-plugins-ugly

sed 's/\n/\t/g' infile

It's not working.
Output should be:

gstreamer-plugins-good    gstreamer-plugins-bad    gstreamer-plugins-ugly
2

normally it can be done by enter in the sed command, you can search in forum, there are many samples, here is the code that no need "enter" in sed command:

sed -n -e "H;\${g;s/\n/ /g;p}" infile

or

tr "\n" " " < infile
3

It is not a space.
It it a tab.

4

so just change it, do you really try to understand the code?

sed -n -e "H;\${g;s/\n/\t/g;p}" infile
tr "\n" "\t" < infile
5

I know the tr command.
The sed command doesn't work.
Compare the sample output.

6 
# cat file
gstreamer-plugins-good
gstreamer-plugins-bad
gstreamer-plugins-ugly

# sed -e :a -e 'N;s/\n/\t/' -e 'ta' file
gstreamer-plugins-good  gstreamer-plugins-bad   gstreamer-plugins-ugly