How to search and find location of a file in linux ?

In linux there are mainly two methods by which a file's location can be searched. They are

1. locate command
2. find command

locate command

locate command is a Unix/*nix command used to find the location of a file. locate searches for a file in a pre-built database which is created with updatedb command or a background process. The syntax for locate command is

locate [option] filename

Examples 

To find the location of a file containing the string file,type 

locate file

Sample Output:

/boot/grub2/i386-pc/configfile.mod
 /boot/grub2/i386-pc/search_fs_file.mod
/etc/filesystems
/etc/profile
/etc/profile.d
/etc/rarfiles.lst
/etc/tmpfiles.d
/etc/cups/cups-files.conf
/etc/dbus-1/system.d/org.kde.nepomuk.filewatch.conf
/etc/dconf/profile
/etc/dconf/profile/gdm
/etc/dconf/profile/ibus
/etc/gconf/schemas/desktop_gnome_file_views.schemas
/etc/gconf/schemas/gnome-media-profiles.schemas
/etc/highlight/filetypes.conf
/etc/kde/env/gtk2_rc_files.sh
/etc/mail/Makefile
/etc/mail/helpfile
/etc/php-zts.d/fileinfo.ini
/etc/php.d/fileinfo.ini
/etc/pki/tls/certs/Makefile
/etc/profile.d/256term.csh
/etc/profile.d/256term.sh
/etc/profile.d/PackageKit.sh
/etc/profile.d/colorgrep.csh
/etc/profile.d/colorgrep.sh
/etc/profile.d/colorls.csh
/etc/profile.d/colorls.sh
/etc/profile.d/kde.csh
/etc/profile.d/kde.sh
/etc/profile.d/lang.csh
/etc/profile.d/lang.sh
/etc/profile.d/less.csh
/etc/profile.d/less.sh
/etc/profile.d/qt-graphicssystem.csh
/etc/profile.d/qt-graphicssystem.sh
/etc/profile.d/qt.csh
/etc/profile.d/qt.sh
/etc/profile.d/vim.csh
/etc/profile.d/vim.sh
/etc/profile.d/vte.sh
/etc/profile.d/which2.csh
:

To locate the file, file2.txt, type

locate file2.txt

Sample Output:

/home/calypso/file2.txt

locate command is fast but you will have to frequently update the database.To update the database run the command updatedb as root user. For more details and options see the man pages

 

find command

find command searches for files in a directory hierarchy.  i.e find command searches through one or more directories specified by the user and locates the required files. find is slower than locate command, but find is more powerful and has more features than locate command. find can search for files based on criteria like name, file type, time, path, size and so on.Syntax for find is

find  [options]  path  [expression]

while using find atleast one path should be mentioned 

Some important filter

-name    - Search for file with the name mentioned

-type     - Search for a file of specific type. Different type filters are listed below

• b      block (buffered) special
• c      character (unbuffered) special
• d      directory
• p      named pipe (FIFO)
• f       regular file
• l       symbolic link
• s      socket

-mtime  - Search files based on the modified time

-atime   - Search files based on accessed time

-size      - Search file based on file size

-user      - Search files by owner


-empty  - Search empty files

Operators

( expr )	Force precedence.
! expr	True if expr is false
-not expr	Same as ! expr, but not POSIX compliant.
expr1 expr2	Two expressions in a row are taken to be joined with an implied "and"; 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.

Some Important Actions

-delete - delete the file

-exec - execute command

-ls - list the file in ls  -dils format

-ok - same as exec but requires user confirmation

-prune - if the file is a directory, do not descend into it

Examples

To find a file named resolv.conf, type

find / -name resolv.conf

The above command searches for files with name resolv.conf under the / directory (i.e. the entire system) and prints the output

Sample Output:

/etc/resolv.conf
/etc/sysconfig/networking/profiles/default/resolv.conf

To find a file name abc.txt under /home/calypso, type

find /home/calypso -name abc.txt

We know linux is case sensitive. In linux abc.txt and ABC.txt are entirely different file. Suppose if you have any confusion over the letter cases in the file name, yo can use find in case insensitive method

find /home/calypso -iname aBc.txt

To find directories with the name jre, type

find / -name jre -type d

The output will list only directories with name jre Sample Output:

/usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64/jre

To find all files whose owner is calypso

find / -user calypso

To find files whose file size is 5 MB

find / -size 5M

To find files whose file size is in between 500 MB and 1GB

find / -size +500M -size -1G

To search and delete all empty files under /home calypso, type

find /home/calypso/ -type f -empty -delete

To find  and remove all regular files under directory /backup, modified 10 days before 

find /backup -type f -mtime +10 -exec rm {} \;

To find all txt files in /home/calypso/Documents/ directory and list them in ls  -dils format, type

find /home/calypso/Documents/ -type f -name "*.txt" -ls

To search all .mp3 files in every  folder of the computer except /home/calypso/songs and its sub-directories, type

find / -path /home/calypso/songs/ -prune -o -type f -name "*.mp3" -print

To find .avi and .mp4 files under /home/calypso,type

find /home/calypso -name '*.avi' -or -name '*.mp4'

                     or

find /home/calypso -name '*.avi' -o -name '*.mp4'

To find all files starting with abc and not ending with .txt, type

find / -name 'abc*' -not -name '*.txt'

               or

find / -name 'abc*' ! -name '*.txt'

find is a very powerful command and can be used in a number of ways based on your requirement. For more details see the man pages