find: Directories
2.10 Directories
================
Here is how to control which directories 'find' searches, and how it
searches them. These two options allow you to process a horizontal
slice of a directory tree.
-- Option: -maxdepth levels
Descend at most LEVELS (a non-negative integer) levels of
directories below the command line arguments. Using '-maxdepth 0'
means only apply the tests and actions to the command line
arguments.
$ mkdir -p dir/d1/d2/d3/d4/d5/d6
$ find dir -maxdepth 1
dir
dir/d1
$ find dir -mindepth 5
dir/d1/d2/d3/d4/d5
dir/d1/d2/d3/d4/d5/d6
$ find dir -mindepth 2 -maxdepth 4
dir/d1/d2
dir/d1/d2/d3
dir/d1/d2/d3/d4
-- Option: -mindepth levels
Do not apply any tests or actions at levels less than LEVELS (a
non-negative integer). Using '-mindepth 1' means process all files
except the command line arguments.
See '-maxdepth' for examples.
-- Option: -depth
Process each directory's contents before the directory itself.
Doing this is a good idea when producing lists of files to archive
with 'cpio' or 'tar'. If a directory does not have write
permission for its owner, its contents can still be restored from
the archive since the directory's permissions are restored after
its contents.
-- Option: -d
This is a deprecated synonym for '-depth', for compatibility with
Mac OS X, FreeBSD and OpenBSD. The '-depth' option is a POSIX
feature, so it is better to use that.
-- Action: -prune
If the file is a directory, do not descend into it. The result is
true. For example, to skip the directory 'src/emacs' and all files
and directories under it, and print the names of the other files
found:
find . -wholename './src/emacs' -prune -o -print
The above command will not print './src/emacs' among its list of
results. This however is not due to the effect of the '-prune'
action (which only prevents further descent, it doesn't make sure
we ignore that item). Instead, this effect is due to the use of
'-o'. Since the left hand side of the "or" condition has succeeded
for './src/emacs', it is not necessary to evaluate the
right-hand-side ('-print') at all for this particular file. If you
wanted to print that directory name you could use either an extra
'-print' action:
find . -wholename './src/emacs' -prune -print -o -print
or use the comma operator:
find . -wholename './src/emacs' -prune , -print
If the '-depth' option is in effect, the subdirectories will have
already been visited in any case. Hence '-prune' has no effect in
this case.
Because '-delete' implies '-depth', using '-prune' in combination
with '-delete' may well result in the deletion of more files than
you intended.
-- Action: -quit
Exit immediately (with return value zero if no errors have
occurred). This is different to '-prune' because '-prune' only
applies to the contents of pruned directories, while '-quit' simply
makes 'find' stop immediately. No child processes will be left
running. Any command lines which have been built by '-exec ... \+'
or '-execdir ... \+' are invoked before the program is exited.
After '-quit' is executed, no more files specified on the command
line will be processed. For example, 'find /tmp/foo /tmp/bar
-print -quit' will print only '/tmp/foo'. One common use of
'-quit' is to stop searching the file system once we have found
what we want. For example, if we want to find just a single file
we can do this:
find / -name needle -print -quit
-- Option: -noleaf
Do not optimize by assuming that directories contain 2 fewer
subdirectories than their hard link count. This option is needed
when searching filesystems that do not follow the Unix
directory-link convention, such as CD-ROM or MS-DOS filesystems or
AFS volume mount points. Each directory on a normal Unix
filesystem has at least 2 hard links: its name and its '.' entry.
Additionally, its subdirectories (if any) each have a '..' entry
linked to that directory. When 'find' is examining a directory,
after it has statted 2 fewer subdirectories than the directory's
link count, it knows that the rest of the entries in the directory
are non-directories ("leaf" files in the directory tree). If only
the files' names need to be examined, there is no need to stat
them; this gives a significant increase in search speed.
-- Option: -ignore_readdir_race
If a file disappears after its name has been read from a directory
but before 'find' gets around to examining the file with 'stat',
don't issue an error message. If you don't specify this option, an
error message will be issued.
Furthermore, 'find' with the '-ignore_readdir_race' option will
ignore errors of the '-delete' action in the case the file has
disappeared since the parent directory was read: it will not output
an error diagnostic, and the return code of the '-delete' action
will be true.
This option can be useful in system scripts (cron scripts, for
example) that examine areas of the filesystem that change
frequently (mail queues, temporary directories, and so forth),
because this scenario is common for those sorts of directories.
Completely silencing error messages from 'find' is undesirable, so
this option neatly solves the problem. There is no way to search
one part of the filesystem with this option on and part of it with
this option off, though. When this option is turned on and find
discovers that one of the start-point files specified on the
command line does not exist, no error message will be issued.
-- Option: -noignore_readdir_race
This option reverses the effect of the '-ignore_readdir_race'
option.
Info Catalog
find: Contents
find: Finding Files
find: Filesystems