Adds the ability to perform file backups before installing newer files on top
of existing ones. Adds a status message about backups to stdout if running in
verbose mode.
The '--backup' option would previously accept arguments separated from the
option either by a space or an equals sign. The GNU implementation strictly
requires an "equals" for argument separation.
As the argument to '--backup' is optional, the equals sign mustn't be ommited
as otherwise there is no way to tell a file argument apart from an argument
that's meant for the '--backup' option. This ensures that if '--backup' is
present it either has no further associated arguments (i.e. fallback to the
default), or the arguments are separated by an equals sign.
Gerenal numeric sort works by comparing pre-parsed floating point
numbers. That means that we don't have to store the &str the float was
parsed from.
As a result, memory usage was slightly reduced for general numeric sort.
`LANGUAGE=C` is not enough, `LC_ALL=C` is needed as the environment
variable that overrides all the other localization settings.
e.g.
```bash
$ LANGUAGE=C id foobar
id: ‘foobar’: no such user
$ LC_ALL=C id foobar
id: 'foobar': no such user
```
* replace `LANGUAGE` with `LC_ALL` as environment variable in the tests
* fix the the date string of affected uutils
* replace `‘` and `’` with `'`
Calling `cmd_keepenv("mv")` spawned the system `mv` instead of
the uutils `mv`. Also, `keepenv` isn't necessary because it doesn't
need to inherit environment variables.
We now actually check the stderr, because previously the result of
`ends_with` was not used, making the test pass even when it shouldn't.
I disabled the test on windows because `mkdir` does not support `-m` on
windows, making the test fail because there will be no permission error.
On FreeBSD there isn't a permission error either, and `mv` succeeds.
Data that was previously boxed inside the `Line` struct was moved to
separate vectors. Inside of each `Line` remains only an index that
allows to access that data.
This helps with keeping the `Line` struct small and therefore reduces
memory usage in most cases.
Additionally, this improves performance because one big allocation (the
vectors) are faster than many small ones (many boxes inside of each
`Line`). Those vectors can be reused as well, reducing the amount of
(de-)allocations.
On some Windows machines this would otherwise cause `std::env::temp_dir`
to fall back to a path that is not writeable (C:\\Windows).
Since by default integration tests don't inherit env vars from the
parent, we have to override this in some cases.
