1. commonly used commands
ls displays the file or directory
-a list all files and directories in the current directory, including hidden a (all)
the -l lists the file details L (List)
-al list all files in the current directory and detailed information, including hidden a (all )
Create a directory mkdir
-p create a directory, if not the parent directory, create a parent directory, such as: mkdir -p parent / child
cd Change directory
cd .. back to the parent directory
back to the root directory cd ~
rmdir to delete empty directories
rm delete files
# rm file name to delete a file, you are prompted to delete
rm -f filename # delete a file, you are not prompted to delete
rm -r / dir / dir1 / dir2 # delete a directory, you are prompted to delete
rm -rf / dir / dir1 / dir2 # delete a directory, you are not prompted to delete
Create an empty file touch
mv move or rename
mv / root / etc / tmp # etc files to / tmp directory
mv aaa abc # file name into abc aaa
cp copy
cp / root / aa / opt / # aa copied to the file directory opt
cp / root / aa / opt / bb # aa file copied to opt directory, and starting a new file name
cp -r / dir / dir1 / dir / dir2 # dir2 copy directory to directory dir1
cp -i # asking to overwrite while copying
find search for a file in the file system
pathname: directory path to find the command you are looking for. For example. To indicate the current directory, / root system is represented. (Example: the Find ./dir/ test.js)
-name find files by file name. (Example: the Find -name test.js)
-perm to find files by file permissions.
-user according to the file owner to locate the file.
-group according to the group the file belongs to locate the file.
-type locate a file type
(b - block device file .d - Catalog .c - character device file .p - pipe files.
L - symbolic link file .f - normal files.)
-print: Find command will match files to standard output.
-size n [c] lookup file block length n files, file length in bytes indicates time with c.
-depth look at the file, first locate the file in the current directory, and then look at its subdirectories
pwd displays the current absolute path
for echo output string
echo "It is a test"> myfile # contents of the left over the right side of the file contents
echo "It is a test" contents >> myfile # appended to the left of the file myfile
(Cat / etc / password> new_pass.txt # content of the left cover to the right of the file contents)
grep is used to find files in qualifying string
# Find filename inside 'str' string
grep 'str' filename
# In the current directory, find the file suffix words have file contains files test string, and print out the line of the string
grep test * file
# Recursively find qualified files. For example, to find the specified directory / etc / acpi and its subdirectories (subdirectories if one exists) all the files that contain the string "update" file, and print out the contents of the line where the string
grep -r update / etc / acpi
ps is used to report the current state of the system process
ps aux | grep amoeba # View amoeba process
#ps displays the current status is in the process of running, grep indicates that the search in these years, but ps aux that all processes and display its status.
ps -ef | grep tomcat-web # View tomcat-web process number
kill -9 process ID # kill process
wc statistics the number of rows of text, words, characters
wc -l # statistics rows
wc -c # number of bytes of
wc counts the number of characters -m #, can not be used in conjunction with -c
wc -w # word count
wc -L # printing longest length
cat / etc / passwd | wc -l # view the file contents, and statistics / etc / passwd file line number
cat / etc / passwd | wc -L # view the file contents, and the length of the longest statistics
cat file path / filename to view the contents of the file
head file path / file name display the first N lines, 10 lines before the default display
The first n lines head -n file path / file name display #
tail file path / file name after the display of N lines, line 10 after the default display
tail -n file path / file name of the file # n lines of the display
tail -f file path / filename # dynamic print file content
date lists current system time
2. The system directory
bin directory: commonly used to store executable file
sbin directory: system used to store executable file
Home directory: / home / username used to store the user's own files or directories
dev directory: device file directory
etc directory: Profiles directory
tmp directory: temporary files directory
/ Opt / media / mnt # free to use
3. User Management
useradd username to add users
useradd -u 100 -g ljp -d / home / ljp -c test # -u 100: uid designated as 100 -g ljp: shared by a group ljp -d / home / ljp: ljp stored in the home directory -c test: Remarks information
passwd username modify user password
Delete user userdel username
su user switch user, loading a configuration file .bashrc (cut only the user name change, environment variables do not change)
su -user switch user, loading a configuration file / etc / profile (run environment variable)
4. File Rights Management
Three basic rights:
R & lt readings expressed as 4
to write the value W is represented as 2
X-values are expressed as an executable
"-Rw-rw-r--" a total of ten characters, divided into four sections.
"-" the first character indicates a normal file; (may also appear "l" link; "D" indicates a directory)
, "rw-" thirty-four second character represents user privileges currently belongs (4 + 2 values are expressed as 6 =)
"rw-" the first five hundred sixty-seven character, represents the rights of the current belongs. (Values are expressed as + 2 =. 6. 4)
"r--" ninety eighth character, showing another user rights (2 values are expressed as
chmod [u belongs to the user group belong g o all users other users a] [+ Permissions increase - decrease permission] [r w x] directory name
chmod 777 text.txt
chmod u+x g+w o+r text.txt
chown to modify the file belongs to group
chown [option] ... [user] [: [group]] files ...
# File1.txt owner of the file to runoob, user groups runoobgroup:
chown runoob: runoobgroup file1.txt
# The current directory of all the files and subdirectories owned by key set runoob, user groups runoobgroup:
chown -R runoob: runoobgroup *
5. System Management Command
who # show online users log on
Display current user whoami #
hostname # show hostname
display system information uname #
ipconfig # View network conditions
Address # ping test network connectivity
netstat # display network status information
top # dynamically display the current resource consumption of the most process information
6. Shutdown / reboot
the shutdown
-r restart shutdown
-h shutdown not restart
now shut down immediately
halt shutdown
reboot reboot
init 0 shutdown
7. file compression decompression process
tar, unpackages
t: View
c f :create filename
v: display the archiving process
z; Compression
x: unpack
tar -cf test.tar a.txt b.txt c.txt # a.txt b.txt c.txt compressed file to test.tar
tar -cvfz test.tar a.txt b.txt c.txt # a.txt b.txt c.txt compressed file to test.tar, displaying the archiving process
tar -tf test.tar # to see which files contain test.tar
tar xvf /tmp/test/test.tar -C / opt / # extracting file directory to opt
gzip compression
gzip test.txt #生成test.txt.gz
gunzip unpacked
gunzip test.txt.gz #生成test.txt