append a character at end of each line of a file

Hi,
i want to append a character '|' at end of each line of a file abc.txt.

for example if the file abc.txt conatins:
a|b|c
1|2|33
w|2|11

i want result file xyz.txt
a|b|c|
1|2|33|
w|2|11|

I know this is simple but sumhow i am not able to reach end of line.
its urgent, thanks for help in advance..

Regards!

sed 's/$/|/g' abc.txt

using Perl:

perl -p -e 'unless (m/\|$/) { s/$/\|/; }' abc.txt > xyz.txt

thanks it worked!!

to prevent double pipe at the end:

sed 's/\([^|]\)$/\1|/' abc.txt