On: Pure Bash Bible – A collection of pure bash alternatives to external processes

[IncRnd]

> Another way to touch a file: cp /dev/null file

That destroys a file, making it 0 bytes. It doesn't touch a file, not at all.

[_kst_ → IncRnd]

And if "file" is the name of an existing directory, it creates an empty file called "file/null".

"touch" exists for a reason.

[cferr → IncRnd]

If the file does not exist, it creates an empty file. That is what most people use touch for.

[IncRnd → cferr]

That's one use case.

The actual use case touch was designed for was to update the timestamp of a file. This is a huge case for developers, since timestamps are used in dependency resolution of partial compilation. [1]

[1] https://man7.org/linux/man-pages/man1/touch.1.html

  NAME
       touch - change file timestamps
  DESCRIPTION
       Update the access and modification times of each FILE to the
       current time.