Summary of common Linux commands (1):
View command help:
1, man command
2. Command --help
Directory switching : cd
cd directory switch directory hierarchy change directory
cd directory/directory
cd .. : the upper level directory
cd / : root directory
cd ~ : go home
Create and delete directories
mkdir create
mkdir directory name
mkdir -pa/b/c, short for mkdir to create directories make directories
mkdir a/b/c.txt iteratively created
rmdir delete
rmdir directory name: only one empty directory can be deleted
Display the list of files in the directory (use ll later)
ls -l(long) -d(directory) displays the abbreviation of directory or file list
ls: Names of visible files (and directories) displayed
ls -a: show the names of all files
A "." in front of a file means a hidden file
ls -l: show file details
Shorthand : ll(★)
ll -h: friendly display
Browse documents
cat: show all the contents of the file
cat filename
more: paging display
Space : next page
carriage return : next line
less: paging display
It can be viewed through the PgUp PgDn page
tail(★★)
View the content of the back of a file
tail - displays the last few lines of filenames
tail -f filename
dynamic viewing
For example :
tail -f catalina.xxx.log
End scrolling with ctrl+c
file manipulation
create a file
touch filename creates a blank file
copy file
cp file directory/filename
For example :
cp 1.txt 2.txt Copy 1.txt and name it 2.txt
cp 1.txt 1/1.txt Copy 1.txt to 1.txt in 1 directory
Move files (rename)
mv file directory/filename
mv filename new filename
-i: ask whether to overwrite if the destination file already exists
-f: enforce, don't ask
-u: If the destination file exists, it will only be moved if it is newer than the source file.
delete file rm
rm filename: delete with query
rm -f filename: delete without asking
rm -r directory: recursive delete with query
rm -rf directory: recursive delete without asking (use with caution)
-r/R --recursive delete all directory layers under this directory at the same time
-f force delete file
To delete a file, generally use rm oldboy.txt. This method will prompt you to confirm, which is recommended for beginners.
The rm -f oldboy.txt method does not prompt for confirmation, but deletes it directly, which is dangerous and is not recommended for beginners.
It is recommended not to use "rm -fr file name" for file deletion . This method of killing chickens with a knife is unnecessary. "rm -f file". rm -fr is generally used to forcefully delete a directory without prompting. very dangerous
tar: package or decompress a file or directory (★★)
Commonly used combinations
-cvf : pack a file or directory
-zcvf: Pack and compress a file or directory Compression format: gzip
-xvf: extract or open a tar file
Format :
tar parameter file name to be packaged | decompressed file directory
For example :
Package all files in the current directory into test1.tar
tar -cvf test1.tar ./*
Package and compress all files in the current directory into test2.tar.gz
tar -zcvf test2.tar.gz ./*
Extract test1.tar to the current directory
tar -xvf test1.tar
Unzip test1.tar to the b directory
tar -xvf test1.tar -C b
Other common commands
grep: find matching strings (★)
grep string
pwd: show the current working directory
wget: download data
wget resource path
vi and vim editor
Edit normal files
Three modes: command line, insert, bottom line mode.
Switch to command line mode: press the Esc key;
Switch to insert mode: press i, o, a keys;
i is inserted before the current position
I insert at the beginning of the current line
a is inserted after the current position
A is inserted at the end of the current line
o Insert a line after the current line
O inserts a row before the current row
Switch to bottom line mode: press : (colon);
vi/vim notepad editor
Execute vi oldboy.txt to enter the vi editor, click a or i (insert abbreviation) to enter the editing mode to start editing the content, after editing, press the esc key to exit the editing mode, and finally press :wq to save and exit the file wq is the abbreviation of Write quit, In the command mode, you can type a colon ":" after the command parameters can be connected. q only save without exit, :wq! force save and exit
> redirection (data flow in the direction of the arrow) overwrites the original file
>> append redirection (data flow in the direction of the arrow) appends content to the end of the original file
cat to view file contents
cat >>oldboy.txt<<EOF XXXXXXX EOF Among them, XXX in the middle of AAA is the content that needs to be written into oldboy.txt, and EOF is the logo and can be replaced by other characters, as long as it is a pair. The EOF at the end needs to be written in freeze frame.
The head header displays the file header -n (number of lines), the default header is 10 lines
The tail of the tail shows the end of the file -n (the number of lines), the default is 10 lines at the end
grep filter function command
What needs to be found (what you want) + filtered files
-v + content to be filtered out (excluded content) + filtered files
sed fetches various content
-n suppress default output
p print
d delete
sed -n /xxx/p file xxx is the content to be queried
sed /^xxx/d file excludes the output of content starting with xxx
Pipe | ★
An important concept whose role is to use the output of one command as the input of another command
For example :
Find the 192.168 string in the results of ifconfig
ifconfig | grep 192.168
Find processes commonly used
Find processes related to java
ps -ef | grep java
Find information about 3306
ps -ef | grep 3306
system management commands
date Display or set the system time
date displays the current system time
date -s "2014-01-01 10:10:10" set the system time
clear clear screen
ctrl+l
ps Status of a running process
ps -ef to view all processes
★ps –ef | grep ssh Find a process
kill kill a process
kill 2868 kills the process numbered 2868
★kill -9 2868 Force kill process
network management
ifconfig: view all network settings
ifconfig NIC name down : disable NIC
ifconfig NIC name up : enable NIC
ping: same as in window
Cancel via ctrl+c
netstat View network ports.
netstat -an | grep 3306 Query the occupancy of port 3306
yum install tree -y install command from internet to server
tree to view the directory structure
LANG=en Temporarily adjust character set