Using sh -c with find

I'm sure everyone reading here has used "-exec" with "find"; for example:

find . -name core -exec rm {} \;

When I want to do something more complex to each found file, I usually pass the name to another script:

find . -exec my shellscript {} \;

The "myshellscript" gets the filename as $1 and you go from there. There is another way to do it, though. Consider this silly example:

find . -exec sh -c '
file=`echo $1 | tr 'c' 'C'`
echo $file' foobah {} \;

The "foobah" is just a convenient way to pass "{}" to the commands. Why wouldn't you just do this?


find . -exec sh -c '
file=`echo $0 | tr 'c' 'C'`
echo $file' {} \;

Well, that wouldn't bother "find" any, but if any of your found files were executable, "find" is going to run them.. so if you happened to have a file named "rm", find would call the real "rm" to remove it. The "foobah" example is really no different: "find" will attempt to run "foobah" for every file found. If you don't know for sure that "foobah" doesn't exist or don't want to chance it, use ":"

find . -exec sh -c '
file=`echo $1 | tr 'c' 'C'`
echo $file' : {} \;

Duh.. what was I thinking? The above is totally wrong: yes, {} gets passed as $1, but it wouldn't be executed. Nor would "foobah" or anything else!

Personally, I find this type of thing more confusing and prefer a separate script.

Comments?

More Articles by Anthony Lawrence - Find me on Google+

Jump to Comments

Many of the products and books I review are things I purchased for my own use. Some were given to me specifically for the purpose of reviewing them. I resell or can earn commissions from the sale of some of these items. Links within these pages may be affiliate links that pay me for referring you to them. That's mostly insignificant amounts of money; whenever it is not I have made my relationship plain. I also may own stock in companies mentioned here. If you have any question, please do feel free to contact me.

Specific links that take you to pages that allow you to purchase the item I reviewed are very likely to pay me a commission. Many of the books I review were given to me by the publishers specifically for the purpose of writing a review. These gifts and referral fees do not affect my opinions; I often give bad reviews anyway.

We use Google third-party advertising companies to serve ads when you visit our website. These companies may use information (not including your name, address, email address, or telephone number) about your visits to this and other websites in order to provide advertisements about goods and services of interest to you. If you would like more information about this practice and to know your choices about not having this information used by these companies, click here.