Fix a bug where `tail -f` would terminate with an error due to failing
to parse a UTF-8 string from a sequence of bytes read from the
followed file. This commit replaces the call to `BufRead::read_line()`
with a call to `BufRead::read_until()` so that any sequence of bytes
regardless of encoding can be read.
Fixes#1050.
Fix a bug when getting all but the first NUM lines or bytes of a file
via `tail -n +NUM <file>` or `tail -c +NUM <file>`. The bug only
existed when a file is given as an argument; it did not exist when the
input data came from stdin.
This makes clap wrap the help text according to the terminal width,
which improves readability for terminal widths < 120 chars,
because clap defaults to a width of 120 chars without this feature.
consistent
* add tests for each flag that takes NUM/SIZE arguments
* fix bug in tail where 'quiet' and 'verbose' flags did not override each other POSIX style
Add some abstractions to simplify the `rbuf_but_last_n_lines()`
function, which implements the "take all but the last `n` lines"
functionality of the `head` program. This commit adds
- `RingBuffer`, a fixed-size ring buffer,
- `ZLines`, an iterator over zero-terminated "lines",
- `TakeAllBut`, an iterator over all but the last `n` elements of an
iterator.
These three together make the implementation of
`rbuf_but_last_n_lines()` concise.
Refactor code from the `backwards_thru_file()` function into a new
`ReverseChunks` iterator, and use that iterator to simplify the
implementation of the `backwards_thru_file()` function. The
`ReverseChunks` iterator yields `Vec<u8>` objects, each of which
references bytes of a given file.
Refactor common code out of two branches of the `unbounded_tail()`
function into a new `unbounded_tail_collect()` helper function, that
collects from an iterator into a `VecDeque` and keeps either the last
`n` elements or all but the first `n` elements.
This commit also adds a new struct, `RingBuffer`, in a new module,
`ringbuffer.rs`, to be responsible for keeping the last `n` elements
of an iterator.
