It isn't quite that simple... Most primaries evaluate to true if and only if some condition is true. (For example the primary -name secret evaluates to true if and only if the name of the file it is currently processing is named secret.) The -prune primary ALWAYS evaluates to true.

For purposes of this discussion, let us assume that we have a file hierarchy rooted in . as shown by

Code:

$ ls -lR .
total 8
drwxr-xr-x  6 dwc  staff  204 Jun 25 17:48 secret
-rwxr-xr-x  1 dwc  staff  141 Jun 26 09:12 tester
drwxr-xr-x  6 dwc  staff  204 Jun 25 17:48 wideopen

./secret:
total 0
-rw-r--r--  1 dwc  staff  0 Jun 25 17:13 1
-rw-r--r--  1 dwc  staff  0 Jun 25 17:13 2
-rw-r--r--  1 dwc  staff  0 Jun 25 17:13 3
-rw-r--r--  1 dwc  staff  0 Jun 25 17:48 secret

./wideopen:
total 0
-rw-r--r--  1 dwc  staff  0 Jun 25 17:13 1
-rw-r--r--  1 dwc  staff  0 Jun 25 17:13 2
-rw-r--r--  1 dwc  staff  0 Jun 25 17:13 3
-rw-r--r--  1 doc  staff  0 Jun 25 17:48 secret

Note the there is a directory named secret in . and regular files named secret in the directories ./secret and ./wideopen.

The -prune primary is different from all of the other primaries. The -prune primary causes files in the file hierarchy under any directory it is given to be ignored (pruned) by find. The -prune primary does NOT prune the name of the directory itself. The other important thing to remember for this discussion is that the find utility by default adds a -print primary to the end of the command line if and only if the arguments supplied by the invoker do NOT include any -print primaries AND do NOT include any -exec command [;|&] primaries and do NOT include any -ok command ; primaries. So if any portion of the primaries in a command separated by -o operators does not include a -print, -ok, or -exec; that set of primaries between -o operators will produce no output. So, surprisingly to some users, the command:

Code:

find . -name secret -prune

does not prune files named secret; instead it produces the output:

Code:

./secret
./wideopen/secret

(i.e., it prints the pathnames of files named secret that are not located in a file hierarchy rooted in a directory named secret so ./secret/secret is not printed) and there is no -o operator to select files that are not named secret.

And the command:

Code:

find . -name secret -prune -o -print

or the logically equivalent:

Code:

find . \( -name secret -a -prune \) -o -print

produces the output:

Code:

.
./tester
./wideopen
./wideopen/1
./wideopen/2
./wideopen/3

By choosing the primaries and operators in your find command, you can choose to have find with -prune print the names of non-directory files with a name matching the names of directories being pruned, but not print the names of pruned directories, and print the pathnames of any files that have not been pruned that are not named secret:

Code:

find . -name secret -type d -prune -o -print

producing:

Code:

.
./tester
./wideopen
./wideopen/1
./wideopen/2
./wideopen/3
./wideopen/secret

or print the pathnames of pruned directories and the pathnames of non-directory files with the names of pruned directories, and print the pathnames of any other files that have not been pruned:

Code:

find . -name secret -prune -type d -print -o ! -name secret -print

producing the output:

Code:

.
./secret
./tester
./wideopen
./wideopen/1
./wideopen/2
./wideopen/3

or both of the above:

Code:

find . -name secret -prune -print -o -print

producing the output:

Code:

.
./secret
./tester
./wideopen
./wideopen/1
./wideopen/2
./wideopen/3
./wideopen/secret