Linux chmod command
Linux chmod command
File calls permissions Linux / Unix is divided into three levels: the file owner, group, others. Use chmod can exercise control over how the file is called by others.
Access: All users
grammar
chmod [-cfvR] [--help] [--version] mode file...
Parameter Description
[ugoa...][[+-=][rwxX]...][,...]
among them:
- u represents the owner of the document, g represents the owner of the file belong to the same group (group) who, o that other people outside, a three represent both.
- + Means increased authority - indicates remove permissions, = represent the only set permissions.
- r represents read, w represents the write, x for executable, X represents only if the file is a subdirectory or the file has been set off as executable.
Examples
Anyone can file file1.txt to read:
chmod ugo+r file1.txt
Anyone can file file1.txt to read:
chmod a+r file1.txt
The file file1.txt with file2.txt to the file owner, it belongs with a group who can write, but others outside of it can not be written:
chmod ug+w,o-w file1.txt file2.txt
Ex1.py will set only the file owner can execute:
chmod u+x ex1.py
The current directory of all the files and subdirectories are set anyone can read:
chmod -R a+r *
In addition chmod you can also use numbers to represent privileges such as:
chmod 777 file
The syntax is:
chmod abc file
Where a, b, c are each a number, respectively permissions User, Group, and Other's.
r = 4, w = 2, x = 1
- To rwx property is 4 + 2 + 1 = 7;
- To rw- property is 4 + 2 = 6;
- To rx property is 4 + 1 = 5.
chmod a=rwx file
and
chmod 777 file
The same effect
chmod ug=rwx,o=x file
and
chmod 771 file
The same effect
If using chmod 4755 filename to make this program has root privileges