Feature parity with GNU head

[chadbrewbaker]

See this line and below. I ran the GNU head test suite against a uu_head binary and added failing unit test cases:

coreutils/tests/by-util/test_head.rs

Line 90 in d878f36

fn test_spams_newline() {

echo -e "a" | uu_head # returns "a\n" not "a"
echo -e "abc" | uu_head -1c # barfs instead of returning "a"
echo -e "a\n" | uu_head -n 2048m # barfs instead of returning "a\n"
echo -e "x\0y" | uu_head  -z -n 1 # barfs instead of returning "x\0"
echo -e "x\0y" | uu_head  -z -n 2 # barfs instead of returning "x\0y"
echo -e "a\n" | uu_head  --bytes=-2 # barfs instead of returning ""
echo -e "a\nb\n" | uu_head  --lines=-0  # "" returns instead of "a\nb\n"

[FelipeLema]

It seems that these tests are already passing? Check my build with the [#ignore]s removed

[SuperSandro2000]

Related #1822

[jfinkels]

I just tested these examples. Taking into account the fact that echo appends a newline character, these are all working as expected. They match the output of GNU head, so I think this can be closed.