main panics when following /dev/stdin since /dev/stdin is not seekable.
Check to see if file is seekable and use unbounded_seek if so.
Also `tail -f` with no files should not follow stdin.
Before each line of content is printed, check if it's from a different
file than the last one we printed for. If so, print a '==> file <=='
header to separate the output in the way tail does.
If multiple files are passed as arguments with the -f option, a vector
of BufReaders is built as the files are first tailed, so that follow()
can take control for the rest of the time the program is running.
follow() loops over each reader and prints all new available content on
each file before moving on to the next.
To get the -f option to follow multiple files, bounded_tail should just
tail a single file and return, instead of blocking processing of other
files by calling follow() (which loops forever).
Makes `parse_size` return a `Result` where the `Err` part indicates whether
there was a parsing error, or the parse size is too big to store. Also makes the
value parsed a `u64` rather than a `usize`.
Adds unit tests for `parse_size` and integration tests using the suffix
multiplier in a number passed with the `-n` flag.
When tailing a file, as opposed to stdin, and we are tailing bytes rather than
lines, we can seek the requested number of bytes from the end of the file. This
side steps the whole `backwards_thru_file` file loop and blocks of reads.
Fixes#833.
When tail'ing a file, we do not need to read the whole file from start to finish
just to find the last n lines or bytes. Instead, we can seek to the end of the
file, and then read the file "backwards" in chunks until we find the location of
the first line/byte we wish to print. This ends up being a nice performance win
for very large files.
Fixes#764
The `BufReader` argument passed to the `fn tail<T: Read>(&mut BufReader<T>,
settings: &settings)` function is never reused, so the `tail` function should
just take ownership of it.
In order to work around lines() removing the newline byte and CRLF, I
switched from the iterator methods (lines/bytes) to the direct methods
(read_line/read). I also manually skipped lines/bytes.
Fixes#744.
For coreutils, there are two build artifacts:
1. multicall executable (each utility is a separate static library)
2. individual utilities (still separate library with main wrapper)
To avoid namespace collision, each utility crate is defined as
"uu_{CMD}". The end user only sees the original utility name. This
simplifies build.rs.
Also, the thin wrapper for the main() function is no longer contained in
the crate. It has been separated into a dedicated file. This was
necessary to work around Cargo's need for the crate name attribute to
match the name in the respective Cargo.toml.
Everything in src/common has been moved to src/uucore. This is defined
as a Cargo library, instead of directly included. This gives us
flexibility to make the library an external crate in the future.
Fixes#717.
Builds the uutils multicall binary containing all utils (except stdbuf)
by default. To only build a subset
`cargo --no-default-features --features <utils>`
can be used.
Whats missing is building the standalone binaries and a mechanism to
automatically disable the build of unix only utils on windows.
I switched over to the getopts crate on crates.io, instead of Rust's
private implementation. This will allow coreutils to build for Rust 1.0.
I'm splitting the updates into several commits for easier reviewing.
I upgraded to the recent Rust release. The only major change was the
reduction of the sleep millisecond resolution from u64 to u32 (this
matches the thread::sleep_ms() method).
