Fix a bug in `tac` where multi-character line separators would cause
incorrect behavior when there was overlap between candidate matches in
the input string. This commit adds a dependency on `memchr` in order to
use the `memchr::memmem::rfind_iter()` function to scan for
non-overlapping instances of the specified line separator characters,
scanning from right to left.
Fixes#2580.
* tac: correct behavior of -b option
Correct the behavior of `tac -b` to match that of GNU coreutils
`tac`. Specifically, this changes `tac -b` to assume *leading* line
separators instead of the default *trailing* line separators.
Before this commit, the (incorrect) behavior was
$ printf "/abc/def" | tac -b -s "/"
def/abc/
After this commit, the behavior is
$ printf "/abc/def" | tac -b -s "/"
/def/abc
Fixes#2262.
* fixup! tac: correct behavior of -b option
* fixup! tac: correct behavior of -b option
Co-authored-by: Sylvestre Ledru <sylvestre@debian.org>
Change the behavior of `tac` when there are no line separators in the
input. Previously, it was appending an extra line separator; this commit
prevents that from happening. The input is now writted directly to
stdout.
Correct the error message produced by `tac` when trying to read from a
directory. Previously if the path 'a' referred to a directory, then
running `tac a` would produce the error message
dir: read error: Invalid argument
after this commit it produces
a: read error: Invalid argument
which matches GNU `tac`.
