Using find for useful tasks

The command find is a powerful tool that can be used for many tasks that operate on a whole directory.

For example, you can find all files that were modified in your home directory in the last 30 minutes with the following use of the find command.

[amit@onyx docs]: find ~ -mmin -30 -print
/home/amit
/home/amit/.kde/share/config
/home/amit/.kde/share/config/kdesktoprc
/home/amit/.kde/share/apps/kalarmd
/home/amit/.kde/share/apps/kalarmd/clients
/home/amit/.Xauthority
/home/amit/.viminfo
/home/amit/public_html/teaching/handouts
/home/amit/public_html/teaching/handouts/cs-linux.tex
/home/amit/public_html/teaching/handouts/.cs-linux.tex.swp
/home/amit/public_html/teaching/253/notes
/home/amit/res/qct/pds/sect7/s7ods_orig.tex
/home/amit/res/qct/pds/sect7/s7ods_hash.tex
/home/amit/.amit-calendar.ics
[amit@onyx docs]:

One of the most powerful uses of find is the ability to execute a command on all files that match the pattern given to find. Here are some examples:

• Remove all files with the name a.out, starting in the current directory and going in all subdirectories recursively.

  find . -name "a.out" -exec /bin/rm -f {} \;
  

  In the above we have to escape the semicolon so that the shell does not process it. Instead the find command needs to process it.

• Find all files in your home directory with the extension .c and remove execute access from those files.

  find ~ -name "*.c" -exec chmod -x  {} \;
  

• Find all files in your home directory with the extension .c or .h and remove execute access from those files.

  find ~ -name "*.[c|h]" -exec chmod -x {} \;
  

  The expression *.[c|h] is an example of a regular expression. Regular expression are a powerful way of expressing a set of possibilities. See man 7 regex for the full syntax of regular expressions.

• Compress all regular files in the directory dir1. This can be handy in saving space in your account.

  find dir1 -type f -exec gzip {} \;
  

• Uncompress all regular files in the directory dir1.

  find dir1 -type f -exec gunzip {} \;