Linux Learning Diary--Basic Command (10)--File search

File Lookup:

File Lookup: Locate, find
Non-real-time lookup (Database lookup): Locate
Real-time Find: Find

Locate
Dependent on pre-built indexes; The index is built automatically when the system is idle (periodic tasks); Manually update the database (UPDATEDB);

The index construction process needs to traverse the whole root file system, consuming resources extremely;

Working characteristics:
Fast search speed;
Fuzzy search;
Non-real-time lookup;

Locate KEYWORD

Find:
Real-time Find tool to complete file search by traversing the file system under the specified path;

Working characteristics:
The search speed is slightly slower;
Accurate search;
Real-time search;

Grammar:
Find [OPTION] ... [Find Path] [Search Criteria] [Handling Action]
Find path: Specify the target path, default to the current directory;
Search criteria: The specified search criteria can be file name, size, type, permissions and other standards, the default is to find all the files under the specified path;
Handling actions: What to do with the eligible files; default output to the screen;

Search criteria:
Search by file name:
-name "file name": Support for using Glob
*, ?, [], [^]
-iname "file name": Letter case insensitive

-regex "pattern": matches the entire file path string with pattern, not just the file name;

According to the genus, the genus Group looks for:
-user USERNAME: Find files belonging to the owner of the specified user;
Group GRPNAME: Find files that belong to a specified group;

-uid UserID: Find the file that belongs to the UID number specified by the owner;
-gid GroupID: Finds files belonging to the specified GID number;

-nouser: Find files that are not owned by the master;
-nogroup: Find files without a group;

Find by file type:
-type Type:
F: Normal file
D: Catalog file
L: Symbolic Link file
S: Socket file
B: Block device files
C: Character device file
P: Pipeline File

Combination conditions:
With:-A
Or:-O
Non:-not,!

! A-a! B =! (A-o B)
! A-o! B =! (A-a B)

depending on the file size, look for:
-size [+|-] #UNIT
Common units: K, M, G

#UNIT: (#-1, #)
-#UNIT: [0,#-1]
+ #UNIT: (#,oo)

based on time stamp:
Take "Day" as the unit;
-atime [+|-]#,
#: [#,#+1]
+#: [#+1,oo]
-#: [0,#]
-mtime
-ctime

In "Minutes" units:
-amin
-mmin
-cmin

Search by permissions:
-perm [/|-]mode
MODE: Exact permission match
/mode: The permission of any class (U,g,o) object can only be matched by one match;
-mode: Each type of object must have a permission standard assigned to it at the same time;

Handling actions:
-print: The default processing action, display to the screen;
-ls: Similar to executing the "ls-l" command on the found file;
-delete: Delete the found file;
-fls/path/to/somefile: Long format information for all files found is saved to the specified file;
-ok COMMAND {} \; Executes commands specified by the command for each file found;
User confirmation is requested interactively before each file executes the command;
-exec COMMAND {} \; Executes commands specified by the command for each file found;
{}: Used to refer to the file name itself;

Note: When find passes the found file to the command specified later, it finds all eligible files once passed to the following command;
Some commands cannot accept too many arguments, at which point the command execution may fail, and another way to circumvent this problem:
Find | Xargs COMMAND

Linux Learning Diary--Basic Command (10)--File search