Input redirection in find -exec option

Question

Why doesn't this command work?

find / -type f -name "*.c" -exec wc -c < \{} \;

I'm trying to hide the filename while showing number of characters

Answer 1

You can do the following:

find / -type f -name "*.c" -exec wc -c {} + | awk '{print $1}'

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< does not work because redirection applies to the find command itself. So what you can do is use awk to only print the first column

As pointed out by @Charles Duffy, this is a bit more efficient since it means we're only starting one wc process, and no shell wrapper, once per file (as the awk instance is shared, not invoked per-file).

Answer 2

Use a bash command with exec like below

find . -type f -name "*.c" -exec bash -c 'wc -c < "$1"' _ {} \;

In your case the redirection < applies to the find command itself resulting a syntax error as there is no file literally named {}.

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^{A sidenote : The positional parameter inside bash shell should be double quoted to deal with non-standard filenames, say those with spaces and so.}

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Edit

To NOT pay the extra cost of invoking multiple sub-shells, we can further improve the exec part like below

find . -type f -name "*.c" -exec bash -c 'for arg; do wc -c <"$arg"; done' _ {} +

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^{Courtesy @Charles Duffy for this suggestion.}

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