An alternative is:

  mv file.name !#:1.bak
  cp process.log !#:1.old

!#:1 expands to the word with index 1.

And it supports regex replace as well

    $ echo foobar !#:1:s/foo/bar
    echo foobar barbar
    foobar barbar

slightly shorter !#$

and i always use ctrl-alt-e to expand and check even if i dont want to edit

I didn't know about the Ctrl-Alt-E so that's useful to know when using a new computer or a shared user account. I have `shopt -s histverify` set in my own bashrc. It's a useful sanity check when using history expansion. After typing the command, press Enter to see what it expands to, verify that it's what I intend and hit Enter a second time to confirm the comand.

Another common rename is the three way:

  mv file file.bak; mv file.new file

Nested {} can handle that one, cutting four 'file's down to one:

  eval mv file{,{.bak\;mv\ ,.new},}

Anyone have a way to hack that to cut the two 'mv's down to one?

> Anyone have a way to hack that to cut the two 'mv's down to one?

Yup:

    mv -bS .bak file{.new,}

Should give the same result if you're using gnu coreutils 'mv', though it's obviously not as generally useful as nested braces.

I didn't know {} could nest!

It sorta can't... note the use of eval.

The eval isn't to help with the nesting. The {} stuff nests just fine, as we can see by changing the "eval mv" to printf:

  $ printf '[%s]' file{,{.bak\;mv,.new},}
  [file][file.bak;mv][file.new][file]

(Note: I took out the '\ ' from the original because I realized it is not necessary).

The eval is there because in bash text expansion occurs after ';' is interpreted, and we need that to be the other way around. Hence, the escaping of ';' in the input to preserve it for text expansion, and then the eval afterward to get ';' interpreted.

Sorry, I should have checked.

I jumped at it because there are other things one might like to achieve with brace expansion but turn out to be impossible because it is evaluated first - you can't use them with variables.