find

 The find command is similar to the ls command, but provides more options and capabilities.  

find files by type

The -type operator takes 'f' or 'd' to only output regular files or directories. The following only finds regular files.

            $ find -type f
        

find directory types

The following only finds directory files.

                $ find -type d
            

find files by name

The -name operator takes a regular expression and uses that against the filename. The following finds files named "*.java"

            $ find -name "*.java"
        

find files not named

The ! operator negates operand to the right. The following is an example of finding files not named *.txt

                $ find . -type f ! -name "*.txt" -print
            

find with grep

Using pipes and xargs, the grep command can works on each file found by the find command. The following finds files named "*.java", pipes that output to xargs, and then greps for the string "import org.gnu".

                $ find . -type f -name "*.java" -print0 | xargs -0 grep "import org.gnu"
            

find and sort the largest 15 files under a directory

                $ find . -type f -printf '%s %p\n' | sort -nr | head -n 15
            

find regular files and print filesize in ascending order with the file path

find -type f -printf "%f  %s %p\n"|sort
		

find regular files and print ordered by the last modified date

find . -type f -printf "%T@ %Tc %p\n" | sort -n