3rd Linux Common Commands (3) _ File Search command

3. File Search command

3.1 File Search: Find

(1) Find command

Command name	Find
Command path	/bin/find
Execute permissions	All Users
Grammar	Find [Search Range] [-options] [match criteria] -name: Search by file name -iname: Search by file name, but ignoring case -inum: Based on I-node lookup -size [+-n]: Based on file size lookup,+n greater than,-n less than, n equals where n is in: the size of the data block (512 bytes, or 0.5K) -amin,cmin,mmin: Find based on time attributes (access, file attributes (such as permissions, owner, etc.)change, file content modify). Back +-time, units minutes, + represents greater than,-indicates less than. -user,-group: Based on owner lookup, owning group lookup -type: Search by text type, f file, D directory, l soft link file -exec/-ok Command {} \; : This is a format that is fixed and is used primarily to perform operations on search results, where-ok asks for an action.

(2) Precautions

①find is a precise match, which is the exact matching condition of the search results.

② if you want to make a fuzzy match, you can add a match condition to match a single character.

③ matching criteria can be connected using-A and-O,-a for and connections,-O for or connections

(3) Application examples

① find file in directory/etc Init: #find/etc–name Init

② Search/etc/for all files with file names beginning with "Init":

#Find /etc–name *init-a–type F

③ look for files that are larger than 80MB and less than 100MB under the root directory:

#Find /-size +163840 –a–size-204800 (100mb=204800*0. 5KB)

④ Find files with owner TestUser under the root directory: #find/-user TestUser

⑤ Find files and directories with properties modified within 5 minutes under/etc: #find/etc–cmin-5

⑥ find the Inittab file under/etc and display its details:

#Findls -ld {} \;

3.2 find files in file repository: Locate

(1) Locate command

Command name	Locate
Command path	/usr/bin/locate
Execute permissions	All Users
Grammar	Locate [-options] [filename] -I: Ignore case

(2) Precautions

① system for file Building database (/VAR/LIB/MLOCATE/MLOCATE.DB) and regular updates, and then directly in the library to find, so the search speed .

The ②locate installation package is named Mlocate (Yum list available | grep locate view), installation method:

Yum-y Install Mlocate, then execute updatedb;

③ the new file will not be paid to the database in time, so UpdateDB is executed. Also note that the files under/TMP cannot be paid to the database.

(3) Application examples:

① find files with file name Inittab in system: $locate Inittab

② find locate this file itself: $locate locate

3.3 Search Directory and alias information: which

(1) which command

Command name	which
Command path	/usr/bin/which
Execute permissions	All Users
Grammar	which command

(2) Application examples:

① to see if the RM command has an alias : #which RM

② Find the command and whether there are aliases in the directory: #which useradd

3.4 Search the directory where the command is located and the Help document path: Whereis

(1) Whereis command

Command name	Whereis
Command path	/usr/bin/whereis
Execute permissions	All Users
Grammar	Whereis [command name]

(2) Application examples:

① View ls command directory and help document path : #whereis ls

3.5 searches for a string-matched line in the file and outputs: grep

(1) grep command

Command name	grep (English literal:global Regular expression print)
Command path	/bin/grep
Execute permissions	All Users
Grammar	Grep–iv [Specify string] File -I: Ignore case -V: Excludes specified strings

(2) Application examples:

① View information about MySQL in the installation log: #grep Mysql/root/install.log

② View the contents of a file in addition to the Comment line :

#grep//^ Indicates the beginning of the line, #是注释的开始

3rd Linux Common Commands (3) _ File Search command