The starting point is the name of the directory where find should start looking for files. The find command examines all files in this directory (and any subdirectories) to see if they meet the specified search criteria. If any do, find performs the specified action on each found file. Here are some of the most useful search criteria options:

-name pattern Find files with names that match the pattern.
-size [+|-] n Find files larger or smaller than a certain size.
-atime [+|-] n Find files accessed before or after a certain date.
-mtime [+|-] n Find files modified before or after a certain date.
-type filetype Find only regular files or only directories.

And here are the actions that can be applied to found files:

-print Print just the names of matching files.
-ls Print the names, dates, sizes, and so on of matching files.
-exec command Execute a command with the file name as input.
-ok command Same as -exec, but asks for confirmation first.

That all might look a bit confusing, so here are some examples to bring things down to earth. To find files (starting in the current directory) with names ending with .data and to print their names, try this:

find . -name '*.data' -print
company.data
donor.data
grades.data
sorted.data
words.data

To find files larger than 40K and print the file names and details (use a minus sign instead of a plus sign to find files smaller than a certain size), issue this command:

find . -size +40k -ls
-rw-rw-r-- hermie users 56720 Jan 16 12:42 bigfile
-rw-rw-r-- hermie users 415206 Feb 27 21:37 largefile
-rw-rw-r-- hermie users 315428 Jan 07 05:23 hugefile

To find files ending with .dat that are smaller than 100K, enter

find . -name *.txt -size -100k -ls
-rw-rw-r-- hermie users 26720 Feb 06 23:52 recipes.txt
-rw-rw-r-- hermie users 506 Feb 18 18:45 poem.txt

To find files that have not been accessed for over 30 days and delete them (by sending their names to the rm command), enter

find . -atime +30 -exec rm {} \;

To find directories (starting in the junk directory) and conditionally delete them (by sending their names to the rmdir command), enter

find junk -type d -ok rmdir {} \;

For more information on the find command, see the find manual.

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