last: fix some hostnames are not shown properly with --hostname option issue 212

[LionelMeli]

No description provided.

[sylvestre]

could you please add a test to make sure we don't regress? thanks

[Copilot]

PR Overview

This PR addresses an issue where the hostname is not displayed properly when using the --hostname option by refactoring the formatting logic.

• Reformats the time and end time output by replacing a computed width with fixed-width fields.
• Moves the hostname output to a separate conditional block to ensure it is printed correctly when required.

Reviewed Changes

File	Description
src/uu/last/src/platform/unix.rs	Adjusts formatting logic for time, end time, and hostname output.

Copilot reviewed 1 out of 1 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (2)

src/uu/last/src/platform/unix.rs:525

• [nitpick] Consider replacing the magic number 12 with a named constant for clarity and maintainability.

write!(buf, " {time:<12}").unwrap_or_default();

src/uu/last/src/platform/unix.rs:526

• [nitpick] Consider replacing the magic number 18 with a named constant for clarity and maintainability.

write!(buf, " {end_time_delta:<18}").unwrap_or_default();

[LionelMeli]

Hello,

the last command doesn't work in mac OS and as I understand cannot work per this post:
https://unix.stackexchange.com/questions/468846/macos-what-file-does-the-command-last-get-its-information-from
and this one: https://superuser.com/questions/128705/ssh-last-login-last-and-os-x#:~:text=It%20seems%20modern%20Mac%20OS which explains " It seems modern Mac OS X records utmp/wtmp/lastlog-like information in the Apple SysLog (asl) database files at /var/log/asl/*."
In fact, after created a Mac OS VM (ventura thanks to quickemu project), the file /var/run/utmpx contains only the 2 entries (overwritten at each login). The uucore::utmpx::Utmpx doesn't fit the Mac OS requierement.

Maybe better to restrict the last command to the (true) *Nix platform? Let's me know.

[LionelMeli]

Hello @sylvestre,
Could I do the same thing as per this PR: #234 (so mark things as unimplemented for systems other than Linux such as macOS)?

[LionelMeli]

Hello,
@cakebaker @sylvestre, any opinions about to put the last command aside for macOS?
Thanks.

[cakebaker]

@LionelMeli yes, doing it like in #234 is fine.

[cakebaker]

I think you can simplify this code to make the intent clearer with something like:

Suggested change

	let ouput = String::from_utf8(result.stdout().to_vec())
	.unwrap_or("Failed to convert output to string".to_string());
	let mut output_result: Vec<&str> = ouput.split('\n').collect();
	// Remove the last 3 lines to compare easier with the expected output (so without the information about the begin of file)
	output_result.truncate(output_result.len() - 3);
	let output_result: Vec<_> = result.stdout_str().lines().take(3).collect();

[cakebaker]

I think there is a typo and it should be fmt instead of ftm.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.00%. Comparing base (1dcb552) to head (e1c094d).
Report is 6 commits behind head on main.

Additional details and impacted files

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[cakebaker]

Thanks for your PR!