Re: How could you load only once a Linux ultility without a batch --input-files kind of option and repeatedly use it on many files? . . .

[Dan Ritter <dsr@randomstring.org>]

Albretch Mueller wrote: 
>  The thing is that I have to call, say sha256sum, on millions of files
> 
>  Probably debian admin people dealing with packaging have to deal with
> the same kinds of issues.

find . -name "*foo" -print 

that confirms that you're getting the files you want. When
you're happy, go with:

find . -name "*foo" -print0 | xargs -0 -p32 sha256sum 

which prints each entry followed by a null; then  xargs picks up
the null-terminated entries and runs sha256sum on each one with
a parallelism of 32. You'll want to tune the parallelism for the
number of cores and disk storage you're using. If your disks are
relatively slow, -p #ofcores is about right. You may be able to
bump it up significantly from there for RAIDs, SSDs, or faster
read devices.

-dsr-