macOS command-line tools you might not know about

Re:macOS command-line tools you might not know about by adrianmonk on Tuesday June 27, 2023 @11:04AM (#36493906)

Not just that, but also all the bytes have to go through an extra pipe. Presumably they're copied an extra time because of this.

When you run "cmd < file", the command reads from stdin, which pulls directly from the file. When you do "cat file | cmd", "cat" opens the file, reads from there, and writes to a pipe. Then "cmd" reads from its stdin, which is a pipe.

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Re:macOS command-line tools you might not know about by chlorion on Tuesday June 27, 2023 @08:56PM (#36500885)

GNU cat will use the copy_file_range syscall when possible!

copy_file_range allows a user land program to copy data between two files without doing any user space work. Instead of reading data into a buffer and writing it back out to the destination, the kernel will somehow manage to move the data for you.

I think this will prevent any extra copies from occurring in situations where it can be used.

https://man.archlinux.org/man/copy_file_range.2

https://git.savannah.gnu.org/cgit/coreutils.git/tree/src/cat...

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