If you can't figure out a one-liner for that, it may be that it'll be too hard to remember and/or alter. One liners are great for trivial transformations, but if they're complex enough to be worth asking about, it's probably better to write a script for.

My exceptions to this rule are:

• Golf fun
• If the slightly complex one-liner is captured in a file, like Makefiles, unix aliases, etc.

That being said, if I do want a one-liner and I'm struggling with it, I usually resort to creating a throw-away script first, then converting it to a one-liner.