1. Contents Related
The representative of the second layer directory
.. on behalf of parent directory
- on behalf of a former working directory
~ Where the identity of the current user's home directory
~ Account on behalf of the user account's home directory
Change directory cd (change directory)
pwd Displays the current working directory (print work directory)
Create a new directory mkdir (make directory) mkdir -p test1 / test2 / test3 / test4 (-p create recursive) mkdir -m 711 test1 (-m set permissions)
rmdir deletes an empty directory
2. Understand PATH, begin to understand all the contents of the file exists in the form of linux
echo $ PATH PATH environment variable print output
mv / bin / ls / root, removed from the bin directory as root move files ls
ls can not see the ls command no such file or directory
/ Root / ls ./ls can use these commands to perform the ls command after you move (the former is an absolute path, the latter is when your pwd is the relative path of / root)
PATH = "$ {PATH}: / root" can also add the / root directory to your PATH environment variable, so that you can continue with the ls command
echo $ PATH PATH environment variable print output at this time again, you can see will be more of a / root
mv / root / ls / bin recovery operation is completed remember your ls file to the bin directory then if the error also can log off and log on again, this time because of the cached point parameters.
3. File Operations
cp -p also copy the file attributes (for backup) -r recursive copy
Precautions: source file information source file is a symbolic link file is a directory for a particular file (FIFO)
rm -r recursive delete (WARNNING !!!) -i cross-examination to avoid deleting the wrong
Rename mv mv test test1 a movable rename
4. File Viewer
cat (concatenate series) (start from the first line of file contents) -n print line number less complex and more used (space page)
tac (display file contents by the last line is the cat against the written)
nl display contents, while the output line number
head and tail niche strategy
od read binary files (usually executable file)
It will give od zzh is shuiB output ASCⅡ code, echo the value of screen output to help deal with
touch create an empty file
5. File Permissions
The default file permissions umask subtracted directory 666 777
chattr -a configuration file hidden attribute of the file can only increase data -i the files can not be deleted is set to be renamed or new data is written to the link (helpful for the security of the system)
touch attrtest chattr + i attrtest rm attrtest prompt can not remove chattr -i attrtest (ROOT operation) (i and adding attributes can not delete the root file)
lsattr can view hidden attributes for log log can be set so that it can only increase -a old data can not be modified and deleted
Some special privileges: SUID SGID SBIT binary systems and process management related
file type observation file
6. Find
Find -a executable file which lists all the commands found in the PATH command instead of the first one found
which ls >>>/bin/ls
which which >>>/usr/bin/which
which -a which >>>/usr/bin/which /n /bin/which
whereis find files by the specific directory
locate records based on database, enter keywords to find the user's file name
find too hard to find too many parameters need to learn
7. small example
