I've always had trouble getting `for` loops to work predictably, so my common loop pattern is this:

    grep -l -r pattern /path/to/files | while read x; do echo $x; done

or the like.

This uses bash read to split the input line into words, then each word can be accessed in the loop with variable `$x`. Pipe friendly and doesn't use a subshell so no unexpected scoping issues. It also doesn't require futzing around with arrays or the like.

One place I do use bash for loops is when iterating over args, e.g. if you create a bash function:

    function my_func() {
        for arg; do
            echo $arg
        done
    }

This'll take a list of arguments and echo each on a separate line. Useful if you need a function that does some operation against a list of files, for example.

Also, bash expansions (https://www.gnu.org/software/bash/manual/html_node/Shell-Par...) can save you a ton of time for various common operations on variables.