What is the syntax for xargs' -I flag argument?

Question

The documentation only states vaguely what it does in words, and I can't find any examples readily on the internet.

So, how can I use the -I flag of xargs? I know it has something to do with string substitution in the argument command, but its not clear how to use it.

Answer 1

From tldr xargs:

- Execute the command once for each input line, replacing any occurrences of the placeholder (here marked as `_`) with the input line:

    arguments_source | xargs -I _ command _ optional_extra_arguments

so, something like this:

$ echo "foo" | xargs -I _ echo "bar-"_
bar-foo

xargs takes the input foo, replaces the _ with it and instead of printing bar-_ prints bar-foo to console