On 2021-05-11 Kurt von Laven <kurt.von.la...@gmail.com> wrote: > Hello,
> When the -r, --no-run-if-empty option is combined with the -d, --delimiter > or -0, --null options, the -r, --no-run-if-empty option does not > take effect. The manual describes the intended behavior of the -r, > --no-run-if-empty option: "If the standard input does not contain any > nonblanks, do not run the command. Normally, the command is run once even > if there is no input. This option is a GNU extension." [...] Hello, it does not totally not work. xargs does not run on *really* empty input even with --delimiter/--null: ametzler@argenau:~$ printf '' | xargs -0 --no-run-if-empty echo blah ametzler@argenau:~$ printf '' | xargs --delimiter X --no-run-if-empty echo blah ametzler@argenau:~$ printf 'aXa' | xargs --delimiter X --no-run-if-empty -n 1 echo blah blah a blah a Which is the important case, since it lets xargs -0 work correctly with commands producing null-delimited lists like find -print0. The documented behavior would not make sense, if the list separator is NULL a space character is content, and not "empty". If one wanted to extend --no-run-if-empty to have consistent behavior it would need not run if the input is totally empty or only consists of separator characters. I do not think it is worth the effort to change the code (and the documentation) I would rather suggest to only change the documentation to say that for --delimiter/--null "non-empty" really means not empty. cu Andreas -- `What a good friend you are to him, Dr. Maturin. His other friends are so grateful to you.' `I sew his ears on from time to time, sure'
