Say I have some arbitrary multi-line text file:
A simpler approach (outputs to stdout, doesn't update the input file):
sed '$ s/.$//' somefile
$is a Sed address that matches the last input line only, thus causing the following function call (
s/.$//) to be executed on the last line only.
s/.$//replaces the last character on the (in this case last) line with an empty string; i.e., effectively removes the last char. (before the newline) on the line.
.matches any character on the line, and following it with
$anchors the match to the end of the line; note how the use of
$in this regular expression is conceptually related, but technically distinct from the previous use of
$as a Sed address.
Example with stdin input (assumes Bash, Ksh, or Zsh):
$ sed '$ s/.$//' <<< $'line one\nline two' line one line tw
To update the input file too (do not use if the input file is a symlink):
sed -i '$ s/.$//' somefile
Note: On OSX, you'd have to use
-i '' instead of just
For an overview of the pitfalls associated with
-i, see the bottom half of my answer here.