this post was submitted on 17 Mar 2024
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[–] [email protected] 91 points 7 months ago* (last edited 7 months ago) (1 children)

The intended use of touch is to update the timestamp right?

[–] [email protected] 100 points 7 months ago (2 children)

Yeah. It could just as well have issued a file not found error when you try to touch a nonexistent file. And we would be none the wiser about what we're missing in the world.

[–] [email protected] 18 points 7 months ago (3 children)

“Do one thing and do it very well” is the UNIX philosophy after all; if you’re 99% likely to just create that missing file after you get a file not found error, why should touch waste your time?

[–] [email protected] 35 points 7 months ago (1 children)

Because now touch does two things.

Without touch, we could "just" use the shell to create files.

: > foo.txt
[–] [email protected] 21 points 7 months ago (1 children)

Touch does one thing from a “contract” perspective:

Ensure the timestamp of is

[–] [email protected] 15 points 7 months ago (2 children)

Systemd also does one thing from a contract perspective: run your system

[–] [email protected] 4 points 7 months ago
[–] [email protected] 1 points 7 months ago

Does it do it well, though?

[–] [email protected] 20 points 7 months ago

with this logic, any command that moves, copies or opens a file should just create a new file if it doesn't exist

and now you're just creating new files without realising just because of a typo

[–] [email protected] 9 points 7 months ago (1 children)

But this directly goes against that philosophy, since now instead of changing timestamps it's also creating files

[–] [email protected] 10 points 7 months ago* (last edited 7 months ago)

You can pass -c to not create a file, but it does go against the philosophy that it creates them by default instead of that being an option

EDIT: Looking closer into the code, it would appear to maybe be an efficiency thing based on underlying system calls

Without that check, touch just opens a file for writing, with no other filesystem check, and closes it

With that check, touch first checks if the file exists, and then if so opens the file for writing

[–] [email protected] 9 points 7 months ago

If you touch -c it should work I guess