cp -r $(printf '%q ' "${fs[@]}") bar 不起作用，但 cp -r bar\ foo foo\ bar foo 能起作用：

yalihupokn@zoqu-endiman:~/Downloads$ ls -A
yalihupokn@zoqu-endiman:~/Downloads$ mkdir 'bar foo' 'foo bar'
yalihupokn@zoqu-endiman:~/Downloads$ ls
'bar foo'  'foo bar'
yalihupokn@zoqu-endiman:~/Downloads$ readarray -t -d $'\n' fs < <(cat<<EOF
> bar foo
> foo bar
> EOF
> )
yalihupokn@zoqu-endiman:~/Downloads$ printf '%q ' "${fs[@]}"
bar\ foo foo\ bar yalihupokn@zoqu-endiman:~/Downloads$ mkdir bar
yalihupokn@zoqu-endiman:~/Downloads$ ls
 bar  'bar foo'  'foo bar'
yalihupokn@zoqu-endiman:~/Downloads$ cp -r $(printf '%q ' "${fs[@]}") bar
cp: cannot stat 'bar\': No such file or directory
cp: cannot stat 'foo': No such file or directory
cp: cannot stat 'foo\': No such file or directory
cp: cannot copy a directory, 'bar', into itself, 'bar/bar'
yalihupokn@zoqu-endiman:~/Downloads$ mkdir foo
yalihupokn@zoqu-endiman:~/Downloads$ cp -r bar\ foo foo\ bar foo
yalihupokn@zoqu-endiman:~/Downloads$ ls foo
'bar foo'  'foo bar'
yalihupokn@zoqu-endiman:~/Downloads$

也许这是因为命令替换以特定的方式传入参数？如果是这样，我该如何修改这种行为以实现我的任务？

例如，在这种情况下，eval 真的是唯一的选项吗，还是有其他办法？

解决方案

你可以直接使用经过正确引用的数组：

cp -r "${fs[@]}" bar