1, linux shutdown and restart
Shutdown:
shutdown -h 10:20 # specified time shutdown
shutdown -h now # immediately shut down
shutdown -h +10 # 10 minutes after shutdown
Shut down the system halt #
Restart:
immediately restart shutdown -r now #
shutdown -r 10:20 # specified time to restart
reboot # reboot
init 6 # reboot
cancel the shutdown shutdown -c #
2, unzip
Linux common compressed file: tar, bzip2, ZIP, RAR
.tar using the tar command operations
.bz2 bzip2 command operation using the
.gz gzip command operation using the
.zip using the unzip command to extract
.rar using the command unzip unrar
The most common is the .tar.gz file, that is, after the tar package, using gzip compression
Create a compressed file:
tar zcvf filename.tar.gz dir /
unzip the file:
tar zxvf filename.tar.gz
3, system and network
3.1
uname -a # output current kernel information
3.2 ps: view the process thread state, and the top is some overlap
ps -eflgrep java # find java thread
3.3 top view cup load load, CPU usage. Some of the highest use of memory or cpu process
top -H p pid # viewing thread status of a process
pidof mysqld # pid mysqld view of
3.4 free view memory, more friendly than the top, including physical and virtual memory swap
3.5
df -h # view disk usage, parameters h, it can be friendly show, -k: display each file system capacity KBytes of, -m: display each file system with a capacity of MBytes
3.6 ifconfig View Address
ping www.baidu.com # view network through barrier
3.7
netstat -ant # tcp view the current connection, from the local port for viewing or ip (ss alternatively)
3.8 yum: Management Pack tool
yum install wget -y # install wget command
3.9 systemctl: management back-office services, and is compatible with the service command
For example, restart MySQL, following a recommendation
service mysql restart
systemctl restart mysqld
3.10 su: used to switch the user
su username
su - username # cleanly switch to another account without the accident, recommended
3.11 View File Size:
du -h filename parameters; -k: KBytes listed in capacity display, -m: lists the capacity to display MBytes
3.12 Disk Format
mkfs -t ext4 / dev / hdc6 # partition / dev / hdc6 (you can specify your own partition) formatted as ext4 file system
4, file belongs to user and group
ls -l # Display user and group attributes of a file and the file belongs, such as:
drwxr-xr-x. 2 root root 6 at 20:04 on July 13 common
drwxr-xr-x is the attribute of the file.
Bit 0 is the [ D] is a directory, [ -] is a file, [ L] is expressed as document links (Link File), [ B] it indicates that the interface device is a device for storage of the files inside (randomly access means), [ C] is expressed as a file inside the device serial port device, such as a keyboard, a mouse (one reading unit)
From the first start, three as a group, are: user attributes, group properties, others attribute (user, group, others), permissions are: read, write, execute (r, w, x), no compared with the appropriate permissions: -
Where digital rights to represent individual scores for each authority:
r :4
w:2
x:1
If none: 0
drwxr-xr-x can be expressed as: 755
4.1 modify their user and group:
charp groupname filename # parameter -r, all subfolders under the filename
chown [-r] username filename
chown [-r] username: groupname filename # also modify the relevant user and group
4.2 modify permissions
chmod 777 a.txt # a.txt to file property to: belongs to the user, group, others are read, write, execute
You may also be used +, -, =, a represents the addition, removal, set, all
chmod u = rwx, g = rw, o = r a.txt # a.txt file attribute is set to: the user belongs to (read, write, execute), set (read and write), the other (read)
chmod ax a.txt # remove all execute permissions
chmod 000 -r / # devastating command
5. Other
5.1 export to set environment variables
export PATH=$PATH:/home/username/java/jdk/bin
5.2 env displays all current environment variables
5.3 whereis want to know the specific path to execute the command
5.4 crontab: linux tool for local job
5.5 date outputs the current system time, the output format designated parameter -s
hwclock: View hardware time
5.6 xargs: reading the input source and then processed line
# Delete all class files
find .|grep .class$ | xargs rm -rvf
5.7 ssh # ssh tunnel, parameters -v, learn more output process
5.8 scp: for file transfer, can also be used to transfer directory, as well as more advanced sftp command
scp a.txt 192.168.1.1:/tmp/a.txt
scp -r a_dir 192.168.1.1:/tmp
5.9 wget: direct download files using the command line, support for HTTP
wget -c http:links
5.10 mysql connection:
MySQL -u root -p -h 192.168.1.1
6, text processing
Statistics: sort, uniq # sort and uniq paired. sort -t specified delimiter, -k used to specify the sort column.
Filter: grep, awk, sed, diff
6.1 pairs of filter content:
Use grep, bring --color parameters, print color can be supported in the terminal, the parameter n is a specified number of output lines, for quick navigation
grep -rm --color filename
If you want to see the contents of the front and rear of a keyword, using ABC parameters:
A: after, before the content of n rows
B: after before, the content of n rows
C: n rows before and after the count content
grep -rm --color keyword -A10 -B2 filename
About 6.2 vim, sed, awk and other advanced knowledge and advanced usage, can be explored in other blog,
Reference Address: https://www.runoob.com/linux/linux-tutorial.html