Linux file Lookup

General statement: files on the server such as the vast starry sky, it is difficult to find a designated star. Fortunately, Linux provides us with two search commands. Search: Locate, find

First, locate:

The Locate command query file requires a database that relies on the system itself, and the database is routinely executed once a day. When we have this database, we can quickly search for files.

The locate relies on four components: the 1./usr/bin/updatedb #更新数据库文件, automatically runs 2./usr/bin/locate #查询功能3 every day through crontab./etc/updatedb.conf #配置查询的条件4. Var/lib/mlocate/mlocate.db #存放文件信息的数据库

How to use: [[email protected] ~]# Locate passwd/etc/passwd/etc/passwd-/etc/pam.d/passwd/etc/security/opasswd/lib64/ Security/pam_passwdqc.so/lib64/security/pam_unix_passwd.so .....

Locate queries are fast, but the lookup criteria are too singular and not real-time. For example, to find the system modified files within 10 minutes, locate can do nothing.

Second, find:

Find searches for a file in the directory structure specified by the condition and performs the specified action. Many search conditions can be customized, the function is very powerful.

Command format: Find [options] [Find path] [find condition] [processing action]

1. Default settings:

Find path: Default current directory;

Search criteria: The default is to find all the files under the path;

Processing action: The default is display, which is echo.

2. Search criteria:

-name "file name" , support the use of globbing;

Ps:file globbing: An asterisk (*) is used to match any character in a file name; Matches a single character in the file, and the square brackets ([several characters]) match any one by one characters in the parentheses. Note: File globbing is not a strict regular expression.

[Email protected] ~]# Find/etc/passwd-name passwd/etc/passwd

-iname "file name", looking for case-insensitive characters;

[[email protected] ~]# Touch Abcd[[email protected] ~]# touch Abcd[[email protected] ~]# LSABCD ABCD Anaconda-ks.cfg in Stall.log Install.log.syslog[[email protected] ~]# find. -name Abcd./abcd[[email protected] ~]# find. -iname ABCD./ABCD./ABCD

-user UserName: Based on owner lookup

-group GroupName: Search by genus Group

-uid UID Lookup based on user ID

-gid GID lookup based on group ID

-nouser: Find a file without a master (PS: If the current user Tom has created a file A, Tom user is now deleted.) File A is not in the main group)

-nogroup: Finding files that are not owned by a group

[Email protected] ~]# useradd tom[[email protected] ~]# passwd tom changing password for user Tom. New Password:bad Password:it is the too Shortbad password:is too simpleretype new Password:passwd:all authentication Tokens updated successfully. [[email protected] ~]# Touch A[[email protected] ~]# chown tom.tom a[[email protected] ~]# Ls-la a-rw-r--r--. 1 tom Tom 0 Dec 01:54 a[[email protected] ~]# userdel-r tom[[email protected] ~]# Ls-la a-rw-r--r--. 1 0 Dec 01:54 a[[email protected] ~]# Find-nouser./a[[email protected] ~]#

3. Combination conditions:

-A: With, while satisfying-o: or-not,!: Non-inverting

[[email protected] ~]# Touch 1 ab[[email protected] ~]# LS1 a ab abcd abcd anaconda-ks.cfg install.log Insta Ll.log.syslog[[email protected] ~]# find-name a-o-name 1./A./1

4. Search by file type or size:

1)-type: Search by File type:

F: Normal file

D: Catalogue

B: Block file

C: Character file

L: Symbolic Link device

P: Named pipe device

S: Socket

[Email protected] ~]# LS1 a AB ABC abcd ABCD anaconda-ks.cfg install.log install.log.syslog test[[email Prot Ected] ~]# find-type d.. /abc./test

2)-size: Search by File size

-size [+|-] #Unit

Eg.-size +2m find files larger than 2M, common units: k,m,g

5. Search by Time stamp:

650) this.width=650; "Style=" background-image:none;border-bottom:0px;border-left:0px;padding-left:0px; padding-right:0px;border-top:0px;border-right:0px;padding-top:0px; "title=" image "border=" 0 "alt=" image "src=" http ://s3.51cto.com/wyfs02/m00/78/bc/wkiol1acx-7hlue1aaapqhdruhs237.png "height="/>

Find can be looked up based on the timestamp of the file:-amin N finds the last n minutes of access to the file in the system-atime n Find the last n hours of access to the file in the system-cmin N find the file in the last n minutes of the system changed file status-ctime N Find the last n days of the system changed the text Document Status file-mmin n Find the last n minutes of the system the file data is changed file-mtime n Find the last n days in the system file data changed file #min after the time is minutes, time followed by the number of days

6. Search by file permissions:

-perm [+|-] mode mode: Exact match +mode: any one of the user's permissions matches, often used to find out whether a particular permission for a class exists-mode: The specified permission bits for each type of user to be checked match

[[Email protected] ~]# ls -ltotal 52-rw-r--r--.  1 root root      0 dec 30 02:01 1-rw-r--r--.  1 root root      0 Dec 30 02:01 22-rwxrwxrwx. 1  500  500      0 dec 30 01:54 a-rw-r--r--.  1 root root      0 dec 30 02:01 abdrwxr-xr-x. 2 root root  4096  dec 30 02:04 abc-rw-r--r--.  1 root root     0  dec 30 01:48 abcd-rw-r--r--.  1 root root     0  DEC 30 01:48 ABCD-RW-------.  1 root root  1417 dec 29  18:56 anaconda-ks.cfg-rw-r--r--.  1 root root 27312 dec 29 18:55  install.log-rw-r--r--. 1 root root  7764 dec 29 18:54 install.log.syslogdrwxr-xr-x.  2 root root  4096 Dec 30 02:04 test[[email protected]  ~]# find -perm 777./a

7. Handling Actions:

Files found, we often have to do such as delete, copy, modify and so on operation

-print: Print on standard output-ls: Output each file information in a long format-exec command {} \;: Executes the specified command on the found file,-ok command {} \;: Interactive-exec find finds the A file is passed to-exec for one time to execute find | Xargs COMMAND

[[email protected] ~]# find /etc -name passwd - print -exec cat  {} \;/etc/pam.d/passwd#%pam-1.0auth        includesystem-authaccount    includesystem-authpassword    substacksystem-auth-password   optionalpam_gnome_keyring.so/etc/passwdroot:x:0:0:root:/root:/ bin/bashbin:x:1:1:bin:/bin:/sbin/nologindaemon:x:2:2:daemon:/sbin:/sbin/nologinadm:x:3:4:adm:/var/adm:/sbin/ Nologinlp:x:4:7:lp:/var/spool/lpd:/sbin/nologinsync:x:5:0:sync:/sbin:/bin/sync 

[Email protected] ~]# Find/etc-name passwd-print-ls/etc/pam.d/passwd785290 4-rw-r--r--1 root root 146 2012/etc/pam.d/passwd/etc/passwd786527 4-rw-r--r--1 root root 1338 Dec 01:55/etc/pass Wd

8.find has a lot of commands, which are often used

-name,-iname,-user,-group,-uid,-gid,-nouser,-nogroup,-size,-type,-atime,-perm,-exec,-ok,-ls
| Xargs COMMAND. If you are not looking for it, you can find it man.

Linux file Lookup