Issues with header based column selection

[learnbyexample]

1. Giving a filename isn't working. Passing stdin works.

$ printf 'a,b,c\n1,2,3\n' > test.csv

# hangs
$ hck -d, -F "a" test.csv
^C

# stdin works
$ printf 'a,b,c\n1,2,3\n' | hck -d, -F "a"
a
1

2. If -F isn't the last option when giving filename, it works, but the header gets printed twice.

$ hck -F "a" -F "b" -d, test.csv
a	b
a	b
1	2

# stdin works as expected again
$ printf 'a,b,c\n1,2,3\n' | hck -F "a" -F "b" -d,
a	b
1	2

3. Last field header isn't being recognized. Works if input is single line without newline.

$ printf 'a,b,c\n1,2,3\n' | hck -d, -F "c"
[2021-07-15T10:39:57Z ERROR hck] No headers matched

$ printf 'a,b,c' | hck -d, -F "c"
c

4. There's no error if there are unmatched headers, but at least one header matched. If this is preferred as the default behavior, adding an option to get error would be useful.

$ printf 'a,b,c\n1,2,3\n' | hck -d, -F "a" -F "xyz"
a
1

[sstadick]

Fixes incoming for all of the above! #27

Thank you for the awesome bug report 👍

[sstadick]

Okay, the v0.5.3 release should have all the fixes. v0.5.2 would raise an error if you excluded a header and it couldn't find that header, which I classified as a bug and fixed with v0.5.3.

[learnbyexample]

Thanks for the quick fix :)