No voids, please


I did a small filtering program to rename files removing spaces and tabs.

I’m experimenting the usage of a pipeline approach to do some transformations upon a starting sets of images, so I’m finding useful to pass filenames through the pipeline (stdout/stdin).

Sometimes, though, I need to use many of these files all at once (e.g. to aggregate them inside the same command) and the easiest way to do this is to cope with file names without spaces. Which is not always the starting situation.

So here I am, re-inventing this wheel:

Basically, sequences of consecutive spaces are all turned into a single "-" character. Files that comply with the no-voids rule are not touched.

It does some attempt to avoid overwriting a pre-existing files, checking for existence and trying to generate a different file name until a free one is found. The mechanism is not perfect though, as it leaves a time window between the check for existence and the file renaming where a new file with that name might be created. Now you know it.

As anticipated, it uses standard input and output to pass the file names. Each line is a file name; output filenames are those without spaces, which might be the input file name if it does not have spaces in the first place. I mean, do what I mean.

Here’s how we would use it:

# Rename all files that have `bar` in their name, but not `foo`, so that
# they don't contain spaces. Then `cat` them all.
$ cat $(ls *bar* | grep -v foo | novoids)

I hope it can be useful! Stay safe and… see you next time.

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