How can I delete a newline if it is the last character in a file?

Question

I have some files that I'd like to delete the last newline if it is the last character in a file. od -c shows me that the command I run does write the file with a trailing new line:

0013600   n   t  >  \n

I've tried a few tricks with sed but the best I could think of isn't doing the trick:

sed -e '$s/\(.*\)\n$/\1/' abc

Any ideas how to do this?

Answer 1

perl -pe 'chomp if eof' filename >filename2

or, to edit the file in place:

perl -pi -e 'chomp if eof' filename

^{[Editor's note: -pi -e was originally -pie, but, as noted by several commenters and explained by @hvd, the latter doesn't work.]}

This was described as a 'perl blasphemy' on the awk website I saw.

But, in a test, it worked.