THE BOOK--Playing The Percentages In Baseball

There’s also mmv, if you happen to be on a *NIX-alike that has it.

Tom,

I’m not a master of many unix shells, but I think that syntax is shell-specific; for example it should work in kornshell, but may not work in c-shell.

Your method is fine, assuming you know enough about where you are operating and what filenames you are operating on ...

1) it assumes your working directory is the directory in which you want to make the changes; the pattern match in the “for” loop is not recursive so you won’t change anything in subdirectories - though possibly this behavior is OS-specific. No recursion may be good, bad or unimportant, depending on what you may have in subdirectories.

2) in your working directory this will rename not just files but also any subdirectory names which contain ‘old’.

3) the pattern you use in the sed replacement will match the first occurrence of ‘old’ in the name, which might not be expected: e.g. bold.old will be renamed bnew.old - probably you can come up with a more precise pattern to avoid that kind of accidental replacement - again if you’re only working with a smallish # of files and you know you won’t get those accidental replacements, this does not matter.

4)I believe the buffer holding the returned string from matching *old* can overflow with an error if too many files match the pattern, though the details of how big that string can safely be are probably OS-specific. I’ve had that sort of overflow error with patterns which matched in the low 1000s of files.

Using the find command can give you more flexibility with concerns 1, 2 and 4

Joe, you are right that it is shell-specific.

I appreciate you pointing out all the potential issues.

It would be helpful if you can offer alternative code as well.

Regarding the different type of ticks, I’ve gotten away from using backticks, as they are hard to read and can’t be nested.  In bash, you can use the following instead:

Because the opening and closing braces are distinct (as opposed to backticks, which use the same symbol at the start and finish), I think it’s a little easier to read and to find mistakes.  And you can use nesting with the ${} form, but not with backticks.