refactor: prefer id over whoami

[anntnzrb]

Replace whoami with id -un for broader compatibility, as id -un is POSIX-compliant, widely available, and reliable. It produces the same output as whoami across environments without issues.

References

• id
• whoami

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Edit 1:
Main source: Linux whoami command and the id command of its successor

The id command of whoami ’s replacement is defined by the POSIX standard, and the implementation is done by various operating system vendors.
Because the POSIX standard is a member of the IEEE standard, the id command is more standardized than the whoami command as a product of standardization, and as long as the operating system supports the POSIX standard, there will be an id command. Therefore, in daily operations, using the standardized id command is more recommended.

[srid]

cc @shivaraj-bh

I thought whoami is the more reliable one?

See juspay/omnix#253

[anntnzrb]

Edited to add main source.

[srid]

I thought whoami is the more reliable one?

See juspay/omnix#253

Ah, n/m. I misunderstood. whoami is more reliable than $USER (which is why a99e8d3). I don't think we ever used id.

Out of curiosity, is there a particular environment in which whoami (as used in the main branch of this repo) fails to work for this use case?