A recent compilation of common Linux commands looks like this
Ls Lists folders and files
Options:
- -a Lists all files in the current directory
- -l Displays the list
- -h Human-friendly interface display
Parameter: The directory to display
Example: Command input: ls -alh./
cd
cd .. Returns the upper directory
CD [path] Switches the ${path} position
PWD Displays the full path of the current directory
Mkdir Creates a directory
options
- -p Creates directories recursively. The -p option is not added and directories can be created level by level
Rmdir Deletes an empty directory
Cp Copies files and directories
options
- -r Indicates the replication directory
- -p Reserved file attributes
Mv (move) Cuts a file or changes its name
Grammar:
Mv [source file or path] [destination directory]
Rm (remove) The operation was deleted
Grammar:
Rm -rf [file or directory]
- -r Deletes a directory
- -f Forcible deletion
Touch create file
Cat View file contents
options
- -n Indicates the row number
More Displays file contents in pages
Grammar:
- More [filename]
- Space or f page feed
- Enter a newline
- Q or Q quits
Less Displays file contents in pages
Syntax: less [filename]
Description:
- The usage of the less command is basically the same as that of the more command, except that the less command can be used to scroll up the page
- Less can be searched by / + enter, and n(next) indicates the next
Head looks at the first few lines of the file
- -n Displays how many lines to view (the first 10 lines of the file are viewed by default)
Tail Checks the last few lines of the file
options
- -n Displays the number of trailing lines (default is 10)
- -f Dynamic display (usually used to monitor log file information)
Ln (link) Generates link files (default: generates hard links)
Grammar:
- Ln -s [source file] [target file]
- -s Creates a soft link
Note:
Soft links can cross partitions, but hard links cannot
Chmod (change mode) Changes the permission of a file or directory
- Chmod [{ugoa} {+-=} {RWX} [folder or directory]]
- [mode=421] [file or directory]
- -r recursion modification
Express permissions numerically:
- R — 4 You can view files and list the contents of directories
- W — 2 Can modify file contents and create and delete files in directories
- X — 1 can execute files and access directories
Chmod -r u+w path Sets the write permission for files in path recursively
Chmod -r 755 path Indicates the permission of files in the path path to rwxr-xr-x
Chown (change owner) Changes the owner of a file or directory
Chowm [user] [file or directory]
CHGRP (change group) Changes the owning group of a file or directory
CHGRP [user group] [file or directory]
Umark-s Displays default permissions for new files
Find file search
Find [search scope]
Matching conditions:
- -name Searches by name
- -iname ignores case to search
- -size Searches based on file size
- -user Searches based on the specified user
- -group Searches based on the specified group
- -cmin Indicates the file whose attributes are changed
- -mmin Indicates that the file content is modified
- -a and
- -o or
- -type File type (f, D, or L)
find /etc -name init
find /etc -name *init*
Find /etc/iname init ignores file case
find /etc -name init -exec ls -l {} ;
Locate finds a file in the file repository
locate inittab
Updatedb updates the file database
Which is the directory where the search command resides
Whereis is the directory where the search command is located
Grep searches the file for lines that match the string and prints
options
- -I is case insensitive
- -v excludes specifying strings
Man (manual) Obtain the help information and configuration files
- Enter Turns the page line by line
- Blank page by page
- /n Searches for the keyword
man 1 cmd
man 5 conf
Short message for the whatis command
Apropos conf Displays simple information about the configuration file
Useradd Adds a new user
Passwd Changes the user password
Passwd username
Who Login information used to view information
W You can view the login details
Write Sends a message to the specified user
CTRL + D ends the save
Wall sends a broadcast message
wall [message]
Ping Tests network connectivity
- -c Specifies the number of requests
Ifconfig (interface configure) Displays and sets nic information
Last and lastlog view current and past login information
Traceroute Displays the routing nodes that the network passes through
Netstat Displays network information
-
-t TCP protocol
-
-u UDP protocol
-
– l listening
-
The -r routing
-
-n Displays the IP address and port number
-
Netstat -tlun Displays the port monitored by the local host
-
Netstat -an Displays all network connections on the local computer
-
Netstat -rn Displays the local routing table
Setup Network
service network restart
Mount Device files to be mounted
mount /dev/sr0 /mnt/cdrom/
Gzip /gunzip compressed file
You can only compress files, not save source files
Tar package directory
Tar [option] [compressed file name] [directory]
- – c packaging
- -v Displays detailed information
- -f Specifies the file name
- -z packaging and compression
The tar decompressed
- Unpack – x
- Z decompression
- -f Decompresses the file
- -v Displays detailed information
zip
Zip option [compressed file name] [file or directory]
- -r Indicates the compressed directory
shutdown
- -c Cancels the previous shutdown command
- -h shutdown
- – r to restart
Process management
Main tasks of process management:
- Health check
- Check the process
- Kill the process
Ps View all processes in the system
- Ps aux view all processes, BSD standard
- Ps-le Views all processes
Top Displays the system health status
Pstree Displays the process tree
Kill To end a process
- Kill -1 pid Restarts the process
- Kill -9 Forcibly terminates the PID
Viewing System Resources
Vmstat Monitors system resources
Vmstat [Refresh time] [Number of repeats]
Dmesg startup kernel check
Free Viewing memory information
Free-m The unit is M
Viewing CPU Information
cat /proc/cpuinfo
Uname Displays kernel information
- -a Details information
- -r Indicates a short message
File /bin/ls you can check whether the system is 32-bit or 64-bit
Lsb_release -a Views the release version
Lsof lists the files that the process calls
System Scheduled Task
- service crond restart
- checkconfig crond on
Crontab Settings of the user
- -e Edits scheduled crontab tasks
- -l Queries crontab tasks
- -r Deletes all crontabs of the user
Standard format: ***** command
File System Management
The disk is divided into isolated areas according to certain rules
Primary partition: A maximum of four partitions
Extended partitions, one at most, and one of the primary partitions.
Logical partition, divided from extended partition.
Ext2, ext3, 16T maximum partition and 2T single file
Ext4 supports 1EB partitions, that is, 1024PB, and 16TB files for a single file
Df -h Command to view file system information
Du Statistics directory or file size
du -sh /home/root