The second weekly summary
1.linux role for individual folders
2. Mount (Mount can be mounted automatically shut down, hanging in the open what does?)
3.ldd View library dependencies program
4. Linux file types: pipes, the character, block device
5. Delete special file "-a" approach
6. The way to generate large files and view binary method
dd if = / dev / zero of = / data / haha bs = 1M count = 1024: 0 to create the binary file is full.
View binary file method
xxd / hexdump -c (see hexadecimal)
7.linux file system:
LSB stratification. The beginning of the file on behalf of hidden files. There are two types of data files: 1. Data 2. case sensitive metadata associated with the file system independent system
8. File Name Rule
9.centOS 7 differs from CentOS 6 of documentation.
10.PWD -P/-L
11. The absolute and relative paths, dirname / basename
12.cd
cd; cd-; cd ~ + (user name).
13.ls
1. A variety of options
of things in 2.ll command does not view when viewing soft-linked files unless behind the increase /14.stat view metadata
Three times file: view, modify time modification of metadata belong to it.
15. wildcard file
16.touch ：
It will refresh all the time touch a file that already exists.
touch not directly use the "" symbol need here \ turn meant
-a, -m, -t, -c and so on17.cp copy command (principle)
18.MV command (principle)
You can only change the name of a single change, rename change can support multiple wildcards. Last match can not + "." Examples
rename "conf" "conf.back" file this right
the rename "conf" "conf.back" "file " This is wrong
rename "conf" "conf.back" " file" * This also can be matched to file beginning of the document.
(Wildcard it "", "" is not recognized in the wildcard)19.rm
Examples: root of all the files in a normal user's home directory, the average user can not see, but you can delete (personal analysis, there are deleted documents on principle, the removal process file is the file name and his inode number from directory the file is deleted, and the average user has all the privileges of the directory, so that ordinary users can force the user to put mv own home directory file, rm does not require mandatory)
20. How to deal with large files
Printing large files take up system memory at any time can cause paralysis of the system, but at the same time someone else is using the file, delete the file at this time, will not immediately deleted by> covering can free up memory.
losf | grep deleted can view deleted but still remain in the memory file
21.tree
22.mkdir
Each option
23.rmdir
When you delete a directory directory must be empty,
24.rm
25.rname
26. A method for generating random numbers
echo {RANDOM%56+1}
seq 56 | sort -R | head -n 1
27. inode
The principle of partition storing data
to generate a large number of empty file method, echo f {1..524288} | xargs touch a limited number of each node partition, which is good limited number of files, when the number of files that fill up will cause: disk space , but can not store data.
When a file operation for a plurality of terminals, a first terminal
of the file is deleted, while still using the other end of the terminal, this time the file is deleted, it will not be deleted, stored in memory.
Relationships Relationship mv rm relationship with inode inode and the 28.cp with the inode.
29. Delete is generally recoverable deleted,
shred can be resolved.
-z indicates the last time coverage achieved using a 0 to
the number of times -n covered by
the investigation help
30. Connecting
1. Soft connecting
different files, the linked file stored in the file path to the source.
Delete the link file, it will not affect the original file, delete the source files connected to
a file on the failure
2. hardwired
with a different file name
even a different name files in addition to other things are the same.
Not across partitions create
command
LN xx
31.file
View file types