Linux basic commands (3)

1 、 ln--link

Meaning: create a linked file

Format: ln [- s] source file... link file path

Add a symbolic link with the-s (create soft connection) option to point to the path of the original file

Note: the source file must be an absolute path equivalent to a "shortcut", also known as a soft connection.

2. Search tool which search tool

Format: which [- a] program name.

Whereis search tool

Format: whereis file name

Set up a location index library and execute the updatedb command (manually generate the database) default location: / var/lib/mlocate/mlocate.db

3. Locate positioning tool format: locate [options]... keyword common command options:

-I: ignore case when looking up

-r: use regular expressions when looking up

4. Find search tool format: find [look in] [search criteria] commonly used search criteria

-type: find by file type

F: ordinary files

D: directory

L: connect the file

B: block device file

C: character device file

-name: find by file name

-a: multiple conditions need to be met at the same time

-o: multiple conditions satisfy any one of them

-size: find by file size

-mtime: find other search criteria by file modification time

-user: search by the user to which the file belongs

-perm: search the permissions of the file

-axdepth: specify the directory depth to look up

/ / find all directories under directory / boot/

/ / find all the ordinary files under the directory / boot/

/ / find the file named tty1/tty2/tty3 under the directory / dev/

/ / find files larger than 2m under the directory / boot/

/ / find the files under the directory / boot/ whose names have begun with vm

Processing the file format found by find: find [range] [condition]-exec processing command {}\

Note: {}: replace each search result,\;: end of processing operation

/ / find all files larger than 2m under the directory / boot/ and display them in a long format

/ / find all files larger than 10m under the directory / boot/ and copy them to the directory / opt/

5 、 cat-Concatenate

Meaning: display file content format: cat [options] File name Common command options:

-n: displays the line number before each line (including blank lines)

/ / View the display information of the network card (display line number).

6. Intercept the head / tail of a file

Head, tail command

Format: head-n file name

Tail-n file name

Note: head/tail displays the first / last ten lines by default

/ / File / etx/passwd displays the first ten lines

/ / File / etx/passwd displays the last ten lines

/ / File / etx/passwd displays the first two lines (either of the following two representations is OK)

7 、 wc-Word Count

Meaning: digital statistics format of files: wc [options] File names Common Command options

-l: calculates the total number of lines of text

-w: count the number of words

-c: calculate the number of bytes in the file

-m: count the number of characters