Notes for common Linux commands

Notes for common Linux commands

This is a frequently used command note when I was a beginner in Linux. I deleted some notes based on my current familiarity. I also used backups to check the notes. I hope you can make reference to the useful ones.

// Output the used content to the screen and only check the syntax
Sh-nx scripts. sh

// Output all current set values
Echo $-

// List the last n commands
History-n
// Write data by default ~ /. Bash_history
History-raw histfiles

// Ignore blank rows-case differences
// To-file can be replaced by '-', which is a standard input.
Diff-bBi from-file to-file

// List all bitwise differences
Cmp-l from-file to-file

// Existence
Test-e filename
// Whether the file exists
Test-f filename
// Whether or not it exists and is (first letter): directory, block device, character device, Socket, pipe, Link
// Existence and permission: r, w, x, u, g, k (Sticky bit), s (not empty)

// Whether file1 is newer or older than file2
Test file1-nt/ot file2
// Whether the file is the same and whether it points to the same iNode to determine the hard link
Test file1-ef file2

// Define the variable type as array, integer, envirnment, readonly
Declare-aixr variable

// Set the prompt and wait description
Read-p "This is hint"-t 30 variable

// Display path without Parameters
// Display as file, alias, builtin
Type-t name

// Convert the text format
Iconv-f frommap-t tomap filename [-o newfile]

// The interval is 1 second. The filtered content is highlighted.
Watch-n 1-d 'pstree | grep sys'

// Find a specific process
Ps-ef | grep xxx
// Observe all processes of the system
Ps aux
// Tree display
Ps axjf

// Count the following parts of the directory (including the current directory)
Ls-l | wc-l

// Copy data locally to the server and use the-r recursive directory
Scp local_file remote_username @ remote_ip: remote_folder/file

// Display processes that only use TCP and are in the listening status
Ss-tpl
// Display the Socket Overview
Ss-s

// Display the processes in the listening status using TCP
Netstat-apt
// Display the NIC list
Netstat-I
// Display route table information
Netstat-r
// Display the network Overview
Netstat-s

// The interval is 2 seconds. The TTL is 255. ping 10 times to a gateway.
Ping-c 10-I 2-t 255-B 8.8.8.8

// List the files whose users are root and whose processes are mysql and whose files are TCP
Lsof-u root-c mysql-I tcp

// Display disk statistics
Vmstat-d
// Display memory statistics
Vmstat-s

// Stop the system service and restart it;-h indicates shutdown;-c cancels the command content;
Shutdown-r
// Halt: shutdown, poweroff: shutdown, reboot: restart, suspend: Sleep
Systemctl reboot

// Display the man page of a command at random
Man $ (ls/bin | shuf | head-1)

// Display inode usage of the file system in a more readable manner
Df-hi

// Display the sum of multiple files in a more readable manner
Du-sh text.txt text2.txt

// Make the time stamp of test1.txtthe same as that of test2.txt
Touch-c test1.txt test2.txt

// Forced, interactive. If this parameter is set, the link file and file attributes are copied.
Cp-pdfi from_file to_file

// Use ASCII, decimal, floating point, octal, and hexadecimal to output text
Od [-cdfox] file_name
// Read the records of the last 10 rows
Tail-n 10 file_name
// Output content except the last 10 rows
Head-n-10 file_name
// Output two rows at a time starting from row 3
More + 3-2 file_name
// Display percentage, row number
Less-mN file_name
// Display all row numbers, merge empty rows, and display TAB
Cat-nsT file_name

// A: When A file (or directory) is accessed, the access time atime will not be modified.
// S: if any modification is made, it will be "synchronized" to the disk
// A: Only content can be added and cannot be deleted or modified.
// C: automatic compression
// D: it will not be backed up by dump
// I: cannot be deleted, renamed, or set link
// S: removed from the disk after deletion
// U: the disk is retained after deletion.
Chattr [+-=] [ASacdistu] file_name

// Search
Whereis file_name
// Ignore case sensitivity and output the first five
Locate-il 5 file_name
// Many parameters: Time-type group permission size
// Search for large files
Find.-type f-size + 800 M-print0 | xargs-0 du-mh | sort-nr
// Search for large Directories
Du-hm -- max-depth = 2 | sort-nr | head-5
Find-name t *. txt
// Find the command location in PATH
Which exc_name

// Compression: For * .tar.gz
Tar-zcvf file_name
// Extract
Tar-zxvf file_name
// View included content
Tar-ztvf file_name

// Create a file-Backup
Dd if = "input_file" of = "output_file" bs = "block_size" count = "number"

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