2015-03-16/2015-03-18linux Directory file Management

Content Summary:
1. Several commands related to the directory
mkdir Follow-p option
RmDir also has a-p option
Rm-r-F Two common options
Cp-r for catalogs, sometimes we use/BIN/CP
MV Rename or move, sometimes we use/BIN/MV, when we are in the MV directory, note that if the target directory exists, then the source directory will be moved to the target directory
2. Text-related commands
Cat-n Display Line numbers
Tac
More

Less

Less/var/log/messages can search for keywords/start press n down to find

Head-n default display starts 10 lines
Tail-n-F Displays the last 10 rows by default

/etc/rc.d/rc.local

Date-s "21:30:30"
Date-s "2015-06-29"

3. Properties of the file or directory
belongs to the main, genus group   
Type    D,-, C, B, L, S, p-----------  directory   normal file   character Charact er   block block  Soft connection link  data structure structures  piping pipe
Permissions   rwx   
Inode Index node
4. Change Permissions
chown  Change the owner, owning group
chmod  change rwx permissions
umask  Specify default permissions, directory 755  file 644, directory without execute permission, I We cannot CD into this directory, but can ls this directory
chattr (-a -i  +a  +i)   filename  Special Permissions     (Modify special permissions) a  can only append   i  cannot change
lsattr                                                                   (view special permissions)

[[email protected] sundong]# chattr + A zk/1.txt 
[[email protected] sundong]# lsattr 
-------------E./zhangkun
-------------E./zk
-------------E./mayang
------ -------E./mz.tar
[[email protected] sundong]# cd ZK
[[email protected] zk]# lsattr 
-----a-------E./1.txt

[email protected] sd]# Echo 123 >> 4.txt
[email protected] sd]# cat 4.txt
123
[email protected] sd]#

>> is additional content
> is covering the original content

Redirection and piping in Linux

http://blog.csdn.net/songyang516/article/details/6758256

5. Search for documents
which
Whereis
Yum Install-y mlocate

UpdateDB

Locate 1.txt

Find/-name messages

/var/log/messages

/etc/vmware-tools/messages

Find/-type b-name ' sd* '

/dev/sda3

/dev/sda2

/dev/sda1

/dev/sda
Find-type-name-mtime-atime-ctime
Stat command to view three time
6. link files under Linux
ln
Soft Connection Hard Connection

The options that LN uses are a '-s ', and if not, create a hard link, plus a soft link.

Extension: 1. The difference between/DEV/SHM and swap http://www.aminglinux.com/bbs/thread-7646-1-1.html

/dev/shm/

One thing to be aware of is the capacity issue, under Linux, which defaults to half the size of memory, using the DF-H command to see

Swap
And swap is the virtual memory of Linux, that is, to open up space on the hard disk when memory is not enough to use as memory, it can be understood as when the/dev/shm space is not enough to occupy swap space. Use Cat/proc/swaps to view

2. Specify the difference between buffer and cache http://www.apelearn.com/bbs/forum.php?mod=viewthread&tid=117&highlight=buffer%2B% 2Bcache

Both are data in RAM. In a nutshell, buffer is about to be written to disk, and the cache is read from disk.

2015-03-16/2015-03-18linux Directory file Management