Datasheet

Phase 1



Working on the Command Line

In addition to the -name criterion, you can search for files in various other ways, such as

by permissions (-perm), file size (-size), and owner (-user). The man page for find details

these options; consult it for more information.

Using locate

The locate command is much less flexible than find, but it’s also much faster. To use

locate, type the command name followed by the name of the file you want to find:

# locate whatis

The locate command works by searching a database that it maintains. (If this database is

out-of-date, typing updatedb as root will update it.) The locate command returns the names

of all the files in the database whose names contain the string you specify. Thus, this command

is likely to return the names of many files that merely contain the string you specify, such as

makewhatis and whatis.1.gz. This can be a real problem if you’re searching for a file with

a short name. The locate database also doesn’t include every directory on the computer, but

it does include enough directories that it’s likely to be a useful tool.

Many Linux distributions actually use a program called slocate rather than

locate. The slocate program is a more security-aware version of the pro-

gram; it checks who’s calling the program and adjusts its output to remove

references to files to which the user shouldn’t have access. Distributions that

use slocate typically create a link called locate so that you can call the pro-

gram using this more common name.

Using whereis

The whereis program searches for files in a restricted set of locations, such as standard binary

file directories, library directories, and man page directories. This tool does not search user

directories or many other locations that are easily searched by find or locate. The whereis

utility is a quick way to find program executables and related files like documentation or con-

figuration files.

The whereis program returns filenames that begin with whatever you type as a search cri-

terion, even if those filenames contain extensions. This feature often turns up configuration

files in /etc, man pages, and similar files. To use the program, type whereis followed by the

name of the program you want to locate. For instance, the following command locates

whatis:

# whereis whatis

whatis: /usr/bin/whatis /usr/X11R6/bin/whatis /usr/bin/X11/whatis

/usr/man/man1/whatis.1.gz /usr/share/man/man1/whatis.1.gz

The result shows the whatis executable (/usr/bin/whatis), links to it in other directo-

ries, and the man page for whatis, including a link in a second location. (Your system might

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