Difference between revisions of "Find notes"

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[[Category:Engineering]]
  
 
== exec versus xargs ==
 
== exec versus xargs ==

Revision as of 12:15, 15 June 2007


exec versus xargs

You see some people pipe find output into xargs, but other people start a command using -exec. You wonder what the difference is. The difference is that xargs is faster. It will intelligently group arguments and feed batches to the subcommand, so it doesn't have to start a new instance of the subcommand for every argument.

Generally I find -exec easier to use because you can easily repeat the found filename in the exec argument. It's easier for me to express exactly what I want to be executed. Of course, some people think the find syntax is wacky. The xargs command comes in handy in other places such as a stream not generated by find, but when using find I stick with -exec unless I have a good reason not to.

You can always do it in a shell loop too:

  for filename in *.png ; do convert $filename `basename $filename .png`.jpg; done

List all extensions in the current directory

This came in handy when I was trying to find out exactly what mime-types I need to care about.

find . | grep -v .svn | xargs -L 1 basename | sed -e "s/.*\(\\.\\s*\)/\\1/" | sort | uniq