POSITIONAL OPTIONS

Positional options always return true. They affect only tests occurring later on the command line.

-daystart

Measure times (for -amin, -atime, -cmin, -ctime, -mmin, and -mtime) from the beginning of today rather than from 24 hours ago. This option only affects tests which appear later on the command line.

-follow

Deprecated; use the -L option instead. Dereference symbolic links. Implies -noleaf. The -follow option affects only those tests which appear after it on the command line. Unless the -H or -L option has been specified, the position of the -follow option changes the behaviour of the -newer predicate; any files listed as the argument of -newer will be dereferenced if they are symbolic links. The same consideration applies to -newerXY, -anewer and -cnewer. Similarly, the -type predicate will always match against the type of the file that a symbolic link points to rather than the link itself. Using -follow causes the -lname and -ilname predicates always to return false.

-regextype type

Changes the regular expression syntax understood by -regex and -iregex tests which occur later on the command line. To see which regular expression types are known, use -regextype help. The Texinfo documentation (see SEE ALSO) explains the meaning of and differences between the various types of regular expression.

-warn, -nowarn

Turn warning messages on or off. These warnings apply only to the command line usage, not to any conditions that find might encounter when it searches directories. The default behaviour corresponds to -warn if standard input is a tty, and to -nowarn otherwise. If a warning message relating to command-line usage is produced, the exit status of find is not affected. If the POSIXLY_CORRECT environment variable is set, and -warn is also used, it is not specified which, if any, warnings will be active.

GLOBAL OPTIONS

Global options always return true. Global options take effect even for tests which occur earlier on the command line. To prevent confusion, global options should specified on the command-line after the list of start points, just before the first test, positional option or action. If you specify a global option in some other place, find will issue a warning message explaining that this can be confusing.

The global options occur after the list of start points, and so are not the same kind of option as -L, for example.

-d

A synonym for -depth, for compatibility with FreeBSD, NetBSD, MacOS X and OpenBSD.

-depth

Process each directory's contents before the directory itself. The -delete action also implies -depth.

-help, --help

Print a summary of the command-line usage of find and exit.

-ignore_readdir_race

Normally, find will emit an error message when it fails to stat a file. If you give this option and a file is deleted between the time find reads the name of the file from the directory and the time it tries to stat the file, no error message will be issued. This also applies to files or directories whose names are given on the command line. This option takes effect at the time the command line is read, which means that you cannot search one part of the filesystem with this option on and part of it with this option off (if you need to do that, you will need to issue two find commands instead, one with the option and one without it).

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.

-maxdepth levels

Descend at most levels (a non-negative integer) levels of directories below the starting-points. Using -maxdepth 0 means only apply the tests and actions to the starting-points themselves.

-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 starting-points.

-mount

Don't descend directories on other filesystems. An alternate name for -xdev, for compatibility with some other versions of find.

-noignore_readdir_race

Turns off the effect of -ignore_readdir_race.

-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.

-version, --version

Print the find version number and exit.

-xdev

Don't descend directories on other filesystems.

TESTS

Some tests, for example -newerXY and -samefile, allow comparison between the file currently being examined and some reference file specified on the command line. When these tests are used, the interpretation of the reference file is determined by the options -H, -L and -P and any previous -follow, but the reference file is only examined once, at the time the command line is parsed. If the reference file cannot be examined (for example, the stat(2) system call fails for it), an error message is issued, and find exits with a nonzero status.

A numeric argument n can be specified to tests (like -amin, -mtime, -gid, -inum, -links, -size, -uid and -used) as

+n

for greater than n,

-n

for less than n,

n

for exactly n.

Supported tests:

-amin n

File was last accessed less than, more than or exactly n minutes ago.

-anewer reference

Time of the last access of the current file is more recent than that of the last data modification of the reference file. If reference is a symbolic link and the -H option or the -L option is in effect, then the time of the last data modification of the file it points to is always used.

-atime n

File was last accessed less than, more than or exactly n*24 hours ago. When find figures out how many 24-hour periods ago the file was last accessed, any fractional part is ignored, so to match -atime +1, a file has to have been accessed at least two days ago.

-cmin n

File's status was last changed less than, more than or exactly n minutes ago.

-cnewer reference

Time of the last status change of the current file is more recent than that of the last data modification of the reference file. If reference is a symbolic link and the -H option or the -L option is in effect, then the time of the last data modification of the file it points to is always used.

-ctime n

File's status was last changed less than, more than or exactly n*24 hours ago. See the comments for -atime to understand how rounding affects the interpretation of file status change times.

-empty

File is empty and is either a regular file or a directory.

-executable

Matches files which are executable and directories which are searchable (in a file name resolution sense) by the current user. This takes into account access control lists and other permissions artefacts which the -perm test ignores. This test makes use of the access(2) system call, and so can be fooled by NFS servers which do UID mapping (or root-squashing), since many systems implement access(2) in the client's kernel and so cannot make use of the UID mapping information held on the server. Because this test is based only on the result of the access(2) system call, there is no guarantee that a file for which this test succeeds can actually be executed.

-false

Always false.

-fstype type

File is on a filesystem of type type. The valid filesystem types vary among different versions of Unix; an incomplete list of filesystem types that are accepted on some version of Unix or another is: ufs, 4.2, 4.3, nfs, tmp, mfs, S51K, S52K. You can use -printf with the %F directive to see the types of your filesystems.

-gid n

File's numeric group ID is less than, more than or exactly n.

-group gname

File belongs to group gname (numeric group ID allowed).

-ilname pattern

Like -lname, but the match is case insensitive. If the -L option or the -follow option is in effect, this test returns false unless the symbolic link is broken.

-iname pattern

Like -name, but the match is case insensitive. For example, the patterns `fo*' and `F??' match the file names `Foo', `FOO', `foo', `fOo', etc. The pattern `*foo*` will also match a file called '.foobar'.

-inum n

File has inode number smaller than, greater than or exactly n. It is normally easier to use the -samefile test instead.

-ipath pattern

Like -path. but the match is case insensitive.

-iregex pattern

Like -regex, but the match is case insensitive.

-iwholename pattern

See -ipath. This alternative is less portable than -ipath.

-links n

File has less than, more than or exactly n hard links.

-lname pattern

File is a symbolic link whose contents match shell pattern pattern. The metacharacters do not treat `/' or `.' specially. If the -L option or the -follow option is in effect, this test returns false unless the symbolic link is broken.

-mmin n

File's data was last modified less than, more than or exactly n minutes ago.

-mtime n

File's data was last modified less than, more than or exactly n*24 hours ago. See the comments for -atime to understand how rounding affects the interpretation of file modification times.

-name pattern

Base of file name (the path with the leading directories removed) matches shell pattern pattern. Because the leading directories are removed, the file names considered for a match with -name will never include a slash, so `-name a/b' will never match anything (you probably need to use -path instead). A warning is issued if you try to do this, unless the environment variable POSIXLY_CORRECT is set. The metacharacters (`*', `?', and `[]') match a `.' at the start of the base name (this is a change in findutils-4.2.2; see section STANDARDS CONFORMANCE below). To ignore a directory and the files under it, use -prune rather than checking every file in the tree; see an example in the description of that action. Braces are not recognised as being special, despite the fact that some shells including Bash imbue braces with a special meaning in shell patterns. The filename matching is performed with the use of the fnmatch(3) library function. Don't forget to enclose the pattern in quotes in order to protect it from expansion by the shell.

-newer reference

Time of the last data modification of the current file is more recent than that of the last data modification of the reference file. If reference is a symbolic link and the -H option or the -L option is in effect, then the time of the last data modification of the file it points to is always used.

-newerXY reference

Succeeds if timestamp X of the file being considered is newer than timestamp Y of the file reference. The letters X and Y can be any of the following letters:

a	The access time of the file reference
B	The birth time of the file reference
c	The inode status change time of reference
m	The modification time of the file reference
t	reference is interpreted directly as a time

Some combinations are invalid; for example, it is invalid for X to be t. Some combinations are not implemented on all systems; for example B is not supported on all systems. If an invalid or unsupported combination of XY is specified, a fatal error results. Time specifications are interpreted as for the argument to the -d option of GNU date. If you try to use the birth time of a reference file, and the birth time cannot be determined, a fatal error message results. If you specify a test which refers to the birth time of files being examined, this test will fail for any files where the birth time is unknown.

-nogroup

No group corresponds to file's numeric group ID.

-nouser

No user corresponds to file's numeric user ID.

-path pattern

File name matches shell pattern pattern. The metacharacters do not treat `/' or `.' specially; so, for example,

find . -path "./sr*sc"

will print an entry for a directory called ./src/misc (if one exists). To ignore a whole directory tree, use -prune rather than checking every file in the tree. Note that the pattern match test applies to the whole file name, starting from one of the start points named on the command line. It would only make sense to use an absolute path name here if the relevant start point is also an absolute path. This means that this command will never match anything:

find bar -path /foo/bar/myfile -print

Find compares the -path argument with the concatenation of a directory name and the base name of the file it's examining. Since the concatenation will never end with a slash, -path arguments ending in a slash will match nothing (except perhaps a start point specified on the command line). The predicate -path is also supported by HP-UX find and is part of the POSIX 2008 standard.

-perm mode

File's permission bits are exactly mode (octal or symbolic). Since an exact match is required, if you want to use this form for symbolic modes, you may have to specify a rather complex mode string. For example `-perm g=w' will only match files which have mode 0020 (that is, ones for which group write permission is the only permission set). It is more likely that you will want to use the `/' or `-' forms, for example `-perm -g=w', which matches any file with group write permission. See the EXAMPLES section for some illustrative examples.

-perm -mode

All of the permission bits mode are set for the file. Symbolic modes are accepted in this form, and this is usually the way in which you would want to use them. You must specify `u', `g' or `o' if you use a symbolic mode. See the EXAMPLES section for some illustrative examples.

-perm /mode

Any of the permission bits mode are set for the file. Symbolic modes are accepted in this form. You must specify `u', `g' or `o' if you use a symbolic mode. See the EXAMPLES section for some illustrative examples. If no permission bits in mode are set, this test matches any file (the idea here is to be consistent with the behaviour of -perm -000).

-perm +mode

This is no longer supported (and has been deprecated since 2005). Use -perm /mode instead.

-readable

Matches files which are readable by the current user. This takes into account access control lists and other permissions artefacts which the -perm test ignores. This test makes use of the access(2) system call, and so can be fooled by NFS servers which do UID mapping (or root-squashing), since many systems implement access(2) in the client's kernel and so cannot make use of the UID mapping information held on the server.

-regex pattern

File name matches regular expression pattern. This is a match on the whole path, not a search. For example, to match a file named ./fubar3, you can use the regular expression `.*bar.' or `.*b.*3', but not `f.*r3'. The regular expressions understood by find are by default Emacs Regular Expressions (except that `.' matches newline), but this can be changed with the -regextype option.

-samefile name

File refers to the same inode as name. When -L is in effect, this can include symbolic links.

-size n[cwbkMG]

File uses less than, more than or exactly n units of space, rounding up. The following suffixes can be used:

The size is simply the st_size member of the struct stat populated by the lstat (or stat) system call, rounded up as shown above. In other words, it's consistent with the result you get for ls -l. Bear in mind that the `%k' and `%b' format specifiers of -printf handle sparse files differently. The `b' suffix always denotes 512-byte blocks and never 1024-byte blocks, which is different to the behaviour of -ls.

The + and - prefixes signify greater than and less than, as usual; i.e., an exact size of n units does not match. Bear in mind that the size is rounded up to the next unit. Therefore -size -1M is not equivalent to -size -1048576c. The former only matches empty files, the latter matches files from 0 to 1,048,575 bytes.

-true

Always true.

-type c

File is of type c:

To search for more than one type at once, you can supply the combined list of type letters separated by a comma `,' (GNU extension).

-uid n

File's numeric user ID is less than, more than or exactly n.

-used n

File was last accessed less than, more than or exactly n days after its status was last changed.

-user uname

File is owned by user uname (numeric user ID allowed).

-wholename pattern

See -path. This alternative is less portable than -path.

-writable

Matches files which are writable by the current user. This takes into account access control lists and other permissions artefacts which the -perm test ignores. This test makes use of the access(2) system call, and so can be fooled by NFS servers which do UID mapping (or root-squashing), since many systems implement access(2) in the client's kernel and so cannot make use of the UID mapping information held on the server.

-xtype c

The same as -type unless the file is a symbolic link. For symbolic links: if the -H or -P option was specified, true if the file is a link to a file of type c; if the -L option has been given, true if c is `l'. In other words, for symbolic links, -xtype checks the type of the file that -type does not check.

-context pattern

(SELinux only) Security context of the file matches glob pattern.

ACTIONS

-delete

Delete files; true if removal succeeded. If the removal failed, an error message is issued. If -delete fails, find's exit status will be nonzero (when it eventually exits). Use of -delete automatically turns on the `-depth' option.

Warnings: Don't forget that the find command line is evaluated as an expression, so putting -delete first will make find try to delete everything below the starting points you specified. When testing a find command line that you later intend to use with -delete, you should explicitly specify -depth in order to avoid later surprises. Because -delete implies -depth, you cannot usefully use -prune and -delete together.

Together with the -ignore_readdir_race option, find 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.

-exec command ;

Execute command; true if 0 status is returned. All following arguments to find are taken to be arguments to the command until an argument consisting of `;' is encountered. The string `{}' is replaced by the current file name being processed everywhere it occurs in the arguments to the command, not just in arguments where it is alone, as in some versions of find. Both of these constructions might need to be escaped (with a `\') or quoted to protect them from expansion by the shell. See the EXAMPLES section for examples of the use of the -exec option. The specified command is run once for each matched file. The command is executed in the starting directory. There are unavoidable security problems surrounding use of the -exec action; you should use the -execdir option instead.

-exec command {} +

This variant of the -exec action runs the specified command on the selected files, but the command line is built by appending each selected file name at the end; the total number of invocations of the command will be much less than the number of matched files. The command line is built in much the same way that xargs builds its command lines. Only one instance of `{}' is allowed within the command, and it must appear at the end, immediately before the `+'; it needs to be escaped (with a `\') or quoted to protect it from interpretation by the shell. The command is executed in the starting directory. If any invocation with the `+' form returns a non-zero value as exit status, then find returns a non-zero exit status. If find encounters an error, this can sometimes cause an immediate exit, so some pending commands may not be run at all. For this reason -exec my-command ... {} + -quit may not result in my-command actually being run. This variant of -exec always returns true.

-execdir command ;

-execdir command {} +

Like -exec, but the specified command is run from the subdirectory containing the matched file, which is not normally the directory in which you started find. As with -exec, the {} should be quoted if find is being invoked from a shell. This a much more secure method for invoking commands, as it avoids race conditions during resolution of the paths to the matched files. As with the -exec action, the `+' form of -execdir will build a command line to process more than one matched file, but any given invocation of command will only list files that exist in the same subdirectory. If you use this option, you must ensure that your $PATH environment variable does not reference `.'; otherwise, an attacker can run any commands they like by leaving an appropriately-named file in a directory in which you will run -execdir. The same applies to having entries in $PATH which are empty or which are not absolute directory names. If any invocation with the `+' form returns a non-zero value as exit status, then find returns a non-zero exit status. If find encounters an error, this can sometimes cause an immediate exit, so some pending commands may not be run at all. The result of the action depends on whether the + or the ; variant is being used; -execdir command {} + always returns true, while -execdir command {} ; returns true only if command returns 0.

-fls file

True; like -ls but write to file like -fprint. The output file is always created, even if the predicate is never matched. See the UNUSUAL FILENAMES section for information about how unusual characters in filenames are handled.

-fprint file

True; print the full file name into file file. If file does not exist when find is run, it is created; if it does exist, it is truncated. The file names /dev/stdout and /dev/stderr are handled specially; they refer to the standard output and standard error output, respectively. The output file is always created, even if the predicate is never matched. See the UNUSUAL FILENAMES section for information about how unusual characters in filenames are handled.

-fprint0 file

True; like -print0 but write to file like -fprint. The output file is always created, even if the predicate is never matched. See the UNUSUAL FILENAMES section for information about how unusual characters in filenames are handled.

-fprintf file format

True; like -printf but write to file like -fprint. The output file is always created, even if the predicate is never matched. See the UNUSUAL FILENAMES section for information about how unusual characters in filenames are handled.

-ls

True; list current file in ls -dils format on standard output. The block counts are of 1 KB blocks, unless the environment variable POSIXLY_CORRECT is set, in which case 512-byte blocks are used. See the UNUSUAL FILENAMES section for information about how unusual characters in filenames are handled.

-ok command ;

Like -exec but ask the user first. If the user agrees, run the command. Otherwise just return false. If the command is run, its standard input is redirected from /dev/null.

The response to the prompt is matched against a pair of regular expressions to determine if it is an affirmative or negative response. This regular expression is obtained from the system if the `POSIXLY_CORRECT' environment variable is set, or otherwise from find's message translations. If the system has no suitable definition, find's own definition will be used. In either case, the interpretation of the regular expression itself will be affected by the environment variables 'LC_CTYPE' (character classes) and 'LC_COLLATE' (character ranges and equivalence classes).

-okdir command ;

Like -execdir but ask the user first in the same way as for -ok. If the user does not agree, just return false. If the command is run, its standard input is redirected from /dev/null.

-print

True; print the full file name on the standard output, followed by a newline. If you are piping the output of find into another program and there is the faintest possibility that the files which you are searching for might contain a newline, then you should seriously consider using the -print0 option instead of -print. See the UNUSUAL FILENAMES section for information about how unusual characters in filenames are handled.

-print0

True; print the full file name on the standard output, followed by a null character (instead of the newline character that -print uses). This allows file names that contain newlines or other types of white space to be correctly interpreted by programs that process the find output. This option corresponds to the -0 option of xargs.

-printf format

True; print format on the standard output, interpreting `\' escapes and `%' directives. Field widths and precisions can be specified as with the printf(3) C function. Please note that many of the fields are printed as %s rather than %d, and this may mean that flags don't work as you might expect. This also means that the `-' flag does work (it forces fields to be left-aligned). Unlike -print, -printf does not add a newline at the end of the string. The escapes and directives are:

-prune

True; if the file is a directory, do not descend into it. If -depth is given, then -prune has no effect. Because -delete implies -depth, you cannot usefully use -prune and -delete together. For example, to skip the directory src/emacs and all files and directories under it, and print the names of the other files found, do something like this:

find . -path ./src/emacs -prune -o -print

-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

OPERATORS

Listed in order of decreasing precedence:

( expr )

Force precedence. Since parentheses are special to the shell, you will normally need to quote them. Many of the examples in this manual page use backslashes for this purpose: `\(...\)' instead of `(...)'.

! expr

True if expr is false. This character will also usually need protection from interpretation by the shell.

-not expr

Same as ! expr, but not POSIX compliant.

expr1 expr2

Two expressions in a row are taken to be joined with an implied -a; expr2 is not evaluated if expr1 is false.

expr1 -a expr2

Same as expr1 expr2.

expr1 -and expr2

Same as expr1 expr2, but not POSIX compliant.

expr1 -o expr2

Or; expr2 is not evaluated if expr1 is true.

expr1 -or expr2

Same as expr1 -o expr2, but not POSIX compliant.

expr1 , expr2

List; both expr1 and expr2 are always evaluated. The value of expr1 is discarded; the value of the list is the value of expr2. The comma operator can be useful for searching for several different types of thing, but traversing the filesystem hierarchy only once. The -fprintf action can be used to list the various matched items into several different output files.

Please note that -a when specified implicitly (for example by two tests appearing without an explicit operator between them) or explicitly has higher precedence than -o. This means that find . -name afile -o -name bfile -print will never print afile.

Simple `find|xargs` approach

•

Find files named core in or below the directory /tmp and delete them.

$ find /tmp -name core -type f -print | xargs /bin/rm -f


    

Note that this will work incorrectly if there are any filenames containing newlines, single or double quotes, or spaces.

Safer `find -print0 | xargs -0` approach

•

Find files named core in or below the directory /tmp and delete them, processing filenames in such a way that file or directory names containing single or double quotes, spaces or newlines are correctly handled.

$ find /tmp -name core -type f -print0 | xargs -0 /bin/rm -f


    

The -name test comes before the -type test in order to avoid having to call stat(2) on every file.

Note that there is still a race between the time find traverses the hierarchy printing the matching filenames, and the time the process executed by xargs works with that file.

Executing a command for each file

•

Run file on every file in or below the current directory.

$ find . -type f -exec file '{}' \;


    

Notice that the braces are enclosed in single quote marks to protect them from interpretation as shell script punctuation. The semicolon is similarly protected by the use of a backslash, though single quotes could have been used in that case also.

In many cases, one might prefer the `-exec ... +` or better the `-execdir ... +` syntax for performance and security reasons.

Traversing the filesystem just once - for 2 different actions

•

Traverse the filesystem just once, listing set-user-ID files and directories into /root/suid.txt and large files into /root/big.txt.

$ find / \


\( -perm -4000 -fprintf /root/suid.txt '%#m %u %p\n' \) , \


\( -size +100M -fprintf /root/big.txt '%-10s %p\n' \)




    

This example uses the line-continuation character '\' on the first two lines to instruct the shell to continue reading the command on the next line.

Searching files by age

•

Search for files in your home directory which have been modified in the last twenty-four hours.

$ find $HOME -mtime 0


    

This command works this way because the time since each file was last modified is divided by 24 hours and any remainder is discarded. That means that to match -mtime 0, a file will have to have a modification in the past which is less than 24 hours ago.

Searching files by permissions

•

Search for files which are executable but not readable.

$ find /sbin /usr/sbin -executable \! -readable -print


    

•

Search for files which have read and write permission for their owner, and group, but which other users can read but not write to.

$ find . -perm 664


    

Files which meet these criteria but have other permissions bits set (for example if someone can execute the file) will not be matched.

•

Search for files which have read and write permission for their owner and group, and which other users can read, without regard to the presence of any extra permission bits (for example the executable bit).

$ find . -perm -664


    

This will match a file which has mode 0777, for example.

•

Search for files which are writable by somebody (their owner, or their group, or anybody else).

$ find . -perm /222


    

•

Search for files which are writable by either their owner or their group.

$ find . -perm /220
$ find . -perm /u+w,g+w
$ find . -perm /u=w,g=w


    

All three of these commands do the same thing, but the first one uses the octal representation of the file mode, and the other two use the symbolic form. The files don't have to be writable by both the owner and group to be matched; either will do.

•

Search for files which are writable by both their owner and their group.

$ find . -perm -220
$ find . -perm -g+w,u+w


    

Both these commands do the same thing.

•

A more elaborate search on permissions.

$ find . -perm -444 -perm /222 \! -perm /111
$ find . -perm -a+r -perm /a+w \! -perm /a+x


    

These two commands both search for files that are readable for everybody (-perm -444 or -perm -a+r), have at least one write bit set (-perm /222 or -perm /a+w) but are not executable for anybody (! -perm /111 or ! -perm /a+x respectively).

Pruning - omitting files and subdirectories

•

Copy the contents of /source-dir to /dest-dir, but omit files and directories named .snapshot (and anything in them). It also omits files or directories whose name ends in '~', but not their contents.

$ cd /source-dir
$ find . -name .snapshot -prune -o \( \! -name '*~' -print0 \) \




| cpio -pmd0 /dest-dir




    

The construct -prune -o \( ... -print0 \) is quite common. The idea here is that the expression before -prune matches things which are to be pruned. However, the -prune action itself returns true, so the following -o ensures that the right hand side is evaluated only for those directories which didn't get pruned (the contents of the pruned directories are not even visited, so their contents are irrelevant). The expression on the right hand side of the -o is in parentheses only for clarity. It emphasises that the -print0 action takes place only for things that didn't have -prune applied to them. Because the default `and' condition between tests binds more tightly than -o, this is the default anyway, but the parentheses help to show what is going on.

•

Given the following directory of projects and their associated SCM administrative directories, perform an efficient search for the projects' roots:

$ find repo/ \


\( -exec test -d '{}/.svn' \; \
-or -exec test -d '{}/.git' \; \
-or -exec test -d '{}/CVS' \; \
\) -print -prune




    

Sample output:

repo/project1/CVS
repo/gnu/project2/.svn
repo/gnu/project3/.svn
repo/gnu/project3/src/.svn
repo/project4/.git


    

In this example, -prune prevents unnecessary descent into directories that have already been discovered (for example we do not search project3/src because we already found project3/.svn), but ensures sibling directories (project2 and project3) are found.

Other useful examples

•

Search for several file types.

$ find /tmp -type f,d,l


    

Search for files, directories, and symbolic links in the directory /tmp passing these types as a comma-separated list (GNU extension), which is otherwise equivalent to the longer, yet more portable:

$ find /tmp \( -type f -o -type d -o -type l \)


    

•

Search for files with the particular name needle and stop immediately when we find the first one.

$ find / -name needle -print -quit


    

•

Demonstrate the interpretation of the %f and %h format directives of the -printf action for some corner-cases. Here is an example including some output.

$ find . .. / /tmp /tmp/TRACE compile compile/64/tests/find -maxdepth 0 -printf '[%h][%f]\n'
[.][.]
[.][..]
[][/]
[][tmp]
[/tmp][TRACE]
[.][compile]
[compile/64/tests][find]


    

Operator precedence surprises

The command find . -name afile -o -name bfile -print will never print afile because this is actually equivalent to find . -name afile -o \( -name bfile -a -print \). Remember that the precedence of -a is higher than that of -o and when there is no operator specified between tests, -a is assumed.

“paths must precede expression” error message

$ find . -name *.c -print
find: paths must precede expression
find: possible unquoted pattern after predicate `-name'?

This happens when the shell could expand the pattern *.c to more than one file name existing in the current directory, and passing the resulting file names in the command line to find like this:

find . -name frcode.c locate.c word_io.c -print

That command is of course not going to work, because the -name predicate allows exactly only one pattern as argument. Instead of doing things this way, you should enclose the pattern in quotes or escape the wildcard, thus allowing find to use the pattern with the wildcard during the search for file name matching instead of file names expanded by the parent shell:

$ find . -name '*.c' -print
$ find . -name \*.c -print