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Sometimes you will need to find files on the system that match given
criteria, such as name and file size. This chapter will show you how to find a
file when you know only part of the file name, and how to find a file whose name
matches a given pattern. You will also learn how to list files and directories
by their size and to find the locations of commands.
NOTE: When you want to find files in a directory whose
contents match a particular pattern, search through the files with
grep---see Searching Text. A
method of searching for a given pattern in the contents of files in different
directories is given in Running Commands on
the Files You Find.
See Info file `find.info', node `Top', for more information on finding files.
- Locate:
Quickly locating files that match a pattern.
- Find:
The find tool is for finding files.
- Listing
Finds: Finding files in directory listings.
- Which:
Locating a command.
The simplest way to find files is with GNU locate. Use it when
you want to list all files on the system whose full path name matches a
particular pattern -- for example, all files with the text `audio'
somewhere in their full path name, or all files ending with `ogg';
locate outputs a list of all files on the system that match the
pattern, giving their full path name. When specifying a pattern, you can use any
of the file name expansion characters (see Specifying File Names
with Patterns).
- To find all the files on the system that have the text
`audio' anywhere in their name, type:
$ locate audio [RET]
- To find all the files on the system whose file names end with the text
`ogg', type:
$ locate *ogg [RET]
- To find all hidden "dotfiles" on the system, type:
$ locate /. [RET]
NOTE: locate searches are not case sensitive.
Sometimes, a locate search will generate a lot of output. Pipe
the output to less to peruse it (see Perusing Text).
Use find to find specific files in a particular directory tree,
specifying the name of the directory tree to search, the criteria to match, and
-- optionally -- the action to perform on the found files. (Unlike most other
tools, you must specify the directory tree argument before any other
options.)
You can specify a number of search criteria, and format the output in various
ways; the following sections include recipes for the most commonly used
find commands, as well as a list of find's most
popular options.
Use find to find files in a directory tree by name. Give the
name of the directory tree to search through, and use the `-name'
option followed by the name you want to find.
- To list all files on the system whose file name is `top',
type:
$ find / -name top [RET]
This command will search all directories on the system to which you have
access; if you don't have execute permission for a directory,
find will report that permission is denied to search the directory.
The `-name' option is case sensitive; use the similar
`-iname' option to find name regardless of case.
This command would match any files whose name consisted of the letters
`top', regardless of case -- including `Top',
`top', and `TOP'.
Use file expansion characters (see Specifying File Names
with Patterns) to find files whose names match a pattern. Give these file
name patterns between single quotes.
- To list all files on the system whose names begin with the characters
`top', type:
$ find / -name 'top*' [RET]
- To list all files whose names begin with the three characters
`top' followed by exactly three more characters, type:
$ find / -name 'top???' [RET]
- To list all files whose names begin with the three characters
`top' followed by five or more characters, type:
$ find / -name 'top?????*' [RET]
- To list all files in your home directory tree that end in
`.tex', regardless of case, type:
$ find ~ -iname '*.tex' [RET]
- To list all files in the `/usr/share' directory tree with the
text `farm' somewhere in their name, type:
$ find /usr/share -name '*farm*' [RET]
Use `-regex' in place of `-name' to search for
files whose names match a regular expression, or a pattern describing a
set of strings (see Regular Expressions
-- Matching Text Patterns).
NOTE: The `-regex' option matches the whole
path name, relative to the directory tree you specify, and not just file names.
To find files of a certain size, use the `-size' option,
following it with the file size to match. The file size takes one of three
forms: when preceded with a plus sign (`+'), it matches all files
greater than the given size; when preceded with a hyphen or minus sign
(`-'), it matches all files less than the given size; with
neither prefix, it matches all files whose size is exactly as
specified. (The default unit is 512-byte blocks; follow the size with
`k' to denote kilobytes or `b' to denote bytes.)
Use the `-empty' option to find empty files -- files whose size
is 0 bytes. This is useful for finding files that you might not need, and can
remove.
- To find all empty files in your home directory tree, type:
$ find ~ -empty [RET]
NOTE: To find the largest or smallest files in a given
directory, output a sorted listing of that directory (see Finding Files in
Directory Listings).
To find files last modified during a specified time, use find
with the `-mtime' or `-mmin' options; the argument you
give with `-mtime' specifies the number of 24-hour periods, and
with `-mmin' it specifies the number of minutes.
To specify a range of time, precede the number you give with either a plus
sign (`+') to match times that are equal to or greater than the
given argument, or a hyphen or minus sign (`-') to match times that
are equal to or less than the given argument.
Include the `-daystart' option to measure time from the
beginning of the current day instead of 24 hours ago.
- To list all of the files in your home directory tree that were modified
yesterday, type:
$ find ~ -mtime 1 -daystart [RET]
- To list all of the files in the `/usr' directory tree that were
modified one year or longer ago, type:
$ find /usr -mtime +356 -daystart [RET]
- To list all of the files in your home directory tree that were modified
from two to four days ago, type:
$ find ~ -mtime 2 -mtime -4 -daystart [RET]
In the preceding example, the combined options `-mtime 2' and
`-mtime -4' matched files that were modified between two and four
days ago.
To find files newer than a given file, give the name of that file as an
argument to the `-newer' option.
To find files newer than a given date, use the trick described in the
find Info documentation: create a temporary file in
`/tmp' with touch whose timestamp is set to the date
you want to search for, and then specify that temporary file as the argument to
`-newer'.
In this example, a temporary file called `/tmp/timestamp' is
written; after the search, you can remove it (see Removing Files and
Directories).
NOTE: You can also find files that were last accessed a
number of days after they were modified by giving that number as an argument to
the `-used' option. This is useful for finding files that get
little use -- files matching `-used +100', say, were accessed 100
or more days after they were last modified.
To find files owned by a particular user, give the username to search for as
an argument to the `-user' option.
The `-group' option is similar, but it matches group ownership
instead of user ownership.
You can also use find to execute a command you specify on each
found file, by giving the command as an argument to the `-exec'
option. If you use the string `'{}'' in the command, this string is
replaced with the file name of the current found file when the command executes.
Mark the end of the command with the string `';''.
In this example, the command grep organic file is
executed for each file that find finds, with file being
the name of each file in turn.
To have find pause and confirm execution for each file it finds,
use `-ok' instead of `-exec'.
You can combine many of find's options to find files that match
multiple criteria.
The following tables describe many other options you can use with
find. The first table lists and describes find's
general options for specifying its behavior. As you will see, find
can take many different options; see its man page or its
info documentation for all of them.
| OPTION |
DESCRIPTION |
-daystart |
Use the beginning of today rather than 24 hours previous for time
criteria.
|
-depth |
Search the subdirectories before each directory. |
-help |
Output a help message and exit.
|
-maxdepth levels |
Specify the maximum number of directory levels to descend in the
specified directory tree. |
-mount or -xdev |
Do not descend directories that have another disk mounted on them.
|
-version |
Output the version number and exit. | The following
table lists and describes find's options for specifying which files
to find. Specify the numeric arguments to these options in one of three ways:
preceded with a plus sign (`+') to match values equal to or greater
than the given argument; preceded with a hyphen or minus sign (`-')
to match values equal to or less than the given argument; or give the number
alone to match exactly that value.
| OPTION |
DESCRIPTION |
-amin minutes |
Time in minutes since the file was last accessed.
|
-anewer file |
File was accessed more recently than file. |
-atime days |
Time in days since the file was last accessed.
|
-cmin minutes |
Time in minutes since the file was last changed. |
-cnewer file |
File was changed more recently than file.
|
-ctime days |
Days since the file was last changed. |
-empty |
File is empty.
|
-group group |
Name of the group that owns file. |
-iname pattern |
Case-insensitive file name pattern to match (`report'
matches the files `Report', `report', `REPORT',
etc.).
|
-ipath pattern |
Full path name of file matches the pattern pattern,
regardless of case (`./r*rt' matches
`./records/report' and `./Record-Labels/ART'. |
-iregex regexp |
Path name of file, relative to specified directory tree, matches the
regular expression regexp, regardless of case
(`t?p' matches `TIP' and `top').
|
-links links |
Number of links to the file (see Giving a File
More than One Name). |
-mmin minutes |
Number of minutes since the file's data was last changed.
|
-mtime days |
Number of days since the file's data was last changed. |
-name pattern |
Base name of the file matches the pattern pattern.
|
-newer file |
File was modified more recently than file. |
-path pattern |
Full path name of file matches the pattern pattern
(`./r*rt' matches `./records/report').
|
-perm access mode |
File's permissions are exactly access mode (see Controlling
Access to Files). |
-regex regexp |
Path name of file, relative to specified directory tree, matches the
regular expression regexp.
|
-size size |
File uses size space, in 512-byte blocks. Append
size with `b' for bytes or `k' for
kilobytes. |
-type type |
File is type type, where type can be
`d' for directory, `f' for regular file, or
`l' for symbolic link.
|
-user user |
File is owned by user. | The following
table lists and describes find's options for specifying what to do
with the files it finds.
| OPTION |
DESCRIPTION |
-exec commands |
Specifies commands, separated by semicolons, to be executed on
matching files. To specify the current file name as an argument to a
command, use `{}'.
|
-ok commands |
Like `-exec' but prompts for confirmation before
executing commands. |
-print |
Outputs the name of found files to the standard output, each followed
by a newline character so that each is displayed on a line of its own. On
by default.
|
-printf format |
Use "C-style" output (the same as used by the printf
function in the C programming language), as specified by string
format. | The following table describes the
variables may be used in the format string used by the
`-printf' option.
| VARIABLE |
DESCRIPTION |
\a |
Ring the system bell (called the "alarm" on older systems).
|
\b |
Output a backspace character. |
\f |
Output a form feed character.
|
\n |
Output a newline character. |
\r |
Output a carriage return.
|
\t |
Output a horizontal tab character. |
\\ |
Output a backslash character.
|
%% |
Output a percent sign character. |
%b |
Output file's size, rounded up in 512-byte blocks.
|
%f |
Output base file name. |
%h |
Output the leading directories of file's name.
|
%k |
Output file's size, rounded up in 1K blocks. |
%s |
Output file's size in bytes. |
The following recipes show how to find the largest and smallest files and
directories in a given directory or tree by listing them by size. They also show
how to find the number of files in a given directory.
To find the largest files in a given directory, use ls to list
its contents with the `-S' option, which sorts files in descending
order by their size (normally, ls outputs files sorted
alphabetically). Include the `-l' option to output the size and
other file attributes.
- To list the files in the current directory, with their attributes, sorted
with the largest files first, type:
$ ls -lS [RET]
NOTE: Pipe the output to less to peruse it (see
Perusing
Text).
To list the contents of a directory with the smallest files first, use
ls with both the `-S' and `-r' options,
which reverses the sorting order of the listing.
- To list the files in the current directory and their attributes, sorted
from smallest to largest, type:
$ ls -lSr [RET]
To output a list of directories sorted by their size -- the size of
all the files they contain -- use du and sort. The
du tool outputs directories in ascending order with the smallest
first; the `-S' option puts the size in kilobytes of each directory
in the first column of output. Give the directory tree you want to output as an
option, and pipe the output to sort with the `-n'
option, which sorts its input numerically.
Use the `-r' option with sort to reverse
the listing and output the largest directories first.
To find the number of files in a directory, use ls and pipe the
output to `wc -l', which outputs the number of lines in its input
(see Counting
Text).
- To output the number of files in the current directory, type:
$ ls | wc -l [RET]
19
$
In this example, the command outputs the text `19', indicating
that there are 19 files in the current directory.
Since ls does not list hidden files by default (see Listing Hidden
Files), the preceding command does not count them. Use ls's
`-A' option to count dot files as well.
This command outputs the text `81', indicating that there are 81
files, including hidden files, in the current directory.
To list the number of files in a given directory tree, and not just
a single directory, use find instead of ls, giving the
special find predicate `\! -type d' to exclude the
listing (and therefore, counting) of directories.
- To list the number of files in the `/usr/share' directory tree,
type:
$ find /usr/share \! -type d | wc -l [RET]
- To list the number of files and directories in the
`/usr/share' directory tree, type:
$ find /usr/share | wc -l [RET]
- To list the number of directories in the `/usr/share'
directory tree, type:
$ find /usr/share \! -type f | wc -l [RET]
Use which to find the full path name of a tool or application
from its base file name; when you give the base file name as an option,
which outputs the absolute file name of the command that would have
run had you typed it. This is useful when you are not sure whether or not a
particular command is installed on the system.
In this example, which output `/usr/bin/perl',
indicating that the perl binary is installed in the
`/usr/bin' directory.
NOTE: This is also useful for determining "which" binary
would execute, should you type the name, since some systems may have different
binaries of the same file name located in different directories. In that case,
you can use which to find which one would execute.
[<--] [Cover] [Table of Contents] [Concept Index] [Program Index] [-->]
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