Dired and find
You can select a set of files for display in a Dired buffer more flexibly by using the find utility to choose the files.
To search for files with names matching a wildcard pattern use M-x find-name-dired. It reads arguments directory and pattern, and chooses all the files in directory or its subdirectories whose individual names match pattern.
The files thus chosen are displayed in a Dired buffer in which the ordinary Dired commands are available.
If you want to test the contents of files, rather than their names, use M-x find-grep-dired. This command reads two minibuffer arguments, directory and regexp; it chooses all the files in directory or its subdirectories that contain a match for regexp. It works by running the programs find and grep. See also M-x grep-find, in Compilation. Remember to write the regular expression for grep, not for Emacs. (An alternative method of showing files whose contents match a given regexp is the % g regexp command, see Marks vs Flags.)
The most general command in this series is M-x find-dired, which lets you specify any condition that find can test. It takes two minibuffer arguments, directory and find-args; it runs find in directory, passing find-args to tell find what condition to test. To use this command, you need to know how to use find.
M-x locate provides a similar interface to the locate program. M-x locate-with-filter is similar, but keeps only lines matching a given regular expression.
The format of listing produced by these commands is controlled by the variable find-ls-option, whose default value specifies using options -ld for ls. If your listings are corrupted, you may need to change the value of this variable.
