Linux Basic Three

Cat: View All (cons: Inconvenient to view when there is more content)

Format: Cat [options] File name

Common Command Options

-N: Add a line number before each line

[Email protected] Desktop]# cat-n/etc/passwd

1 Root:x:0:0:root:/root:/bin/bash

2 Bin:x:1:1:bin:/bin:/sbin[em]e188[/em]login

3 Daemon:x:2:2:daemon:/sbin:/sbin[em]e188[/em]login

4 Adm:x:3:4:adm:/var/adm:/sbin[em]e188[/em]login

Less: Split-screen reading (view full content)

Format: less [option] file name

Basic operations

Press PgUp to page forward, PgDn page backward

By? Key forward, press/Backward lookup (N,n toggle)

[Email protected] ~]# LESS/ETC/PASSWD

——————————————————————————————————

Head: Intercept file header

Format: Head-n numeric file name

[[email protected] ~]# head-n 3/etc/passwd (first 3 lines shown)

Root:x:0:0:root:/root:/bin/bash

Bin:x:1:1:bin:/bin:/sbin[em]e188[/em]login

Daemon:x:2:2:daemon:/sbin:/sbin[em]e188[/em]login

————————————————————————————————————————

Tail: Intercepting file tails

Format: Tail-n numeric file name

[[email protected] ~]# tail-n 3/etc/passwd (shown after 3 lines)

Tcpdump:x:72:72::/:/sbin[em]e188[/em]login

Anonymous:x:1000:1000:anonymous:/home/anonymous:/bin/bash

Xxx:x:1001:1001::/home/xxx:/bin/bash

——————————————————————————————————————

Echo: redirect | (;: overwrite redirect, >>: Append redirect)

[Email protected] home]# echo xx >>/home/ls.help

————————————————————————————————————————

|: Pipeline operation (the result of the previous command is treated as a parameter of the following command)

[Email protected] ~]# HEAD-12/ETC/PASSWD | Tail-5

Halt:x:7:0:halt:/sbin:/sbin/halt

Mail:x:8:12:mail:/var/spool/mail:/sbin[em]e188[/em]login

Operator:x:11:0:operator:/root:/sbin[em]e188[/em]login

Games:x:12:100:games:/usr/games:/sbin[em]e188[/em]login

Ftp:x:14:50:ftp User:/var/ftp:/sbin[em]e188[/em]login

——————————————————————————————————————————————

WC: Text Statistics

Format: WC [option] File name

Common Command Options

-L: Calculates the total number of rows of text

-W: Calculates the number of words

-C: Calculate the number of bytes in a file

-M: Count the number of characters

(equivalent to-LWS when there is no option)

————————————————————————————————————————————————

grep retrieves the line of text conditionally

Purpose: Outputs the line containing the specified string

Format: grep [options] ' Find criteria ' target file

Common Command Options

-L: Ignore case when speeding

-V: Reverse lookup, output rows that do not match the find criteria

--color: Highlighting a Find string

Search criteria: Specify a string to find within double quotation marks

^xx: denotes starting with XX

xx$: means ending with XX

^$: Indicates a blank line

[Email protected] ~]# grep-v ' ^$ '/etc/default/useradd

# useradd defaults file

group=100

Home=/home

Inactive=-1

Expire=

Shell=/bin/bash

Skel=/etc/skel

Create_mail_spool=yes

[Email protected] ~]# grep-v ' a '/etc/passwd

Bin:x:1:1:bin:/bin:/sbin[em]e188[/em]login

Sync:x:5:0:sync:/sbin:/bin/sync

(In most Linux configuration files, the part that starts with # represents the comment text)

————————————————————————————————————————————————-

Compression and archiving

Zip compression: A cross-platform compressed file format,

Format: Zip Compressed package Name compressed file

Combine option-R to package a directory

Unzip decompression operation

Format: Unzip [-D destination folder]. zip Archive Package

Tar Production archive

Format: tar [options] archive file, original file or directory

Tar Release archive

Format: tar [options] Archive file [-C target directory]

Common options for the tar command

-C: Create an archive file in. tar format

-X: Unpack the. Tar archive file

-C: Unpacking is the target folder for the specified release

-F: Indicates the use of an archive file

-Z,-J,-J: Call GZIP,BZIP2,XZ compression/decompression, respectively

-V: Output details

-T: List view files in package

(The leading character of the option '-' can be omitted when extracting the archive, the option-z,-j,-j can be omitted, the tar command can automatically identify the package format)

[Email protected] ~]# TAR-ZCF hydra.tar.gz/bin//etc/passwd

Tar: Remove the Beginning "/" from the member name

[[email protected] ~]# ls

anaconda-ks.cfg hydra.tar.gz public Picture Download desktop

home.xx initial-setup-ks.cfg Template Document Music

[Email protected] ~]# TAR-JCF xxx.tar.bz2/bin//etc/passwd

Tar: Remove the Beginning "/" from the member name

[Email protected] ~]# TAR-JCF x.tar.xz/boot/

Tar: Remove the Beginning "/" from the member name

[[email protected] ~]# ls

Anaconda-ks.cfg hydra.tar.gz x.tar.xz public Picture Download desktop

home.xx initial-setup-ks.cfg xxx.tar.bz2 Template Document Music

[Email protected] ~]# TAR-CJF usrsbin.tar.bz2/usr/sbin/

Tar: Remove the Beginning "/" from the member name

Tar: Remove the Beginning "/" from the hard connection target

[Email protected] ~]# TAR-TF usrsbin.tar.bz2

usr/sbin/

Usr/sbin/xfs_copy

Usr/sbin/rtmon

Usr/sbin/build-locale-archive

[Email protected] ~]# TAR-XF usrsbin.tar.bz2-c/root/usrsbin/

————————————————————————————————————————————————

Program and File Lookup

Which: Finding programs

Find: Find the most common search criteria {based on the exact criteria, find by type, find by name, find by size, search by file modification time, process find to file}

Format: Find [Look in] [find criteria]

Common search criteria

-type: Find by File type

-name: Find by file name

-size: Find by File size

-mtime: Search by content modification time (+1,1 days ago, -1,1 days)

F: Normal file

D: Catalogue

L: Connection File

B: Block device files

C: Character device file

[[email protected] boot]# find/root/-type l-exec ls-l {} \; (Displays the link file under the root directory. and show detailed properties)

lrwxrwxrwx. 1 root root 67 May 16:48/root/.mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}/[email protected]/usr /lib64/firefox/langpacks/[email protected]

lrwxrwxrwx. 1 root root 6 April 20:18/root/usrsbin/usr/sbin/ctstat-Lnstat

lrwxrwxrwx. 1 root root 5 April 20:17/root/usrsbin/usr/sbin/btrfsck, Btrfs

Locate: File location

Search by keyword

Linux Basic Three