Add text at the end of each line ... HELP !

[asgro]

Thanks Gintaras for fast reply but probably I didn't explain myself well.


I have one file name " example.txt " ( he is located in directory c:\desktop )

In this file there are about 10 thousand line as follow :

asdf,fdsa,zxcv,,,
1233,qwewdssd,qwerw,,,
9a8id,109274,asdf,,,
lkjh,df,ksajdfds,,,
and so on 

I need to write the word " test " at the end of each line (all are in the same file)

The new "example.txt" file will be :
asdf,fdsa,zxcv,,,test
1233,qwewdssd,qwerw,,,test
9a8id,109274,asdf,,,test
lkjh,df,ksajdfds,,,test

I need to add the word test to each of the contents of the file and overwrite the old file (or generate a new one with name "Complete").

Waiting and thanks for your invaluable help !