文件或目录的存取权限
Permissions, important and tricky!
Unix permissions concern who can read a file or directory, write to it, and execute it. Permissions are granted or withheld with a magic 3-digit number. The three digits correspond to the owner (you); the group (?); and the world (everyone else).
Think of each digit as a sum:
|
? |
execute permission |
= 1 |
|
? |
write permission |
= 2 |
|
? |
write and execute (1+2) |
= 3 |
|
? |
read permission |
= 4 |
|
? |
read and execute (4+1) |
= 5 |
|
? |
read and write (4+2) |
= 6 |
|
? |
read, write and execute (4+2+1) |
= 7 |
Add the number value of the permissions you want to grant each group to make a three digit number, one digit each for the owner, the group, and the world. Here are some useful combinations. Try to figure them out!
修改方式1：以绝对方式改变权限
chmod 600 {filespec}You can read and write; the world can't. Good for files.
chmod 700 {filespec}You can read, write, and execute; the world can't. Good for scripts.
chmod 644 {filespec}You can read and write; the world can only read. Good for web pages.
chmod 755 {filespec}You can read, write, and execute; the world can read and execute. Good for programs you want to share, and your public_html directory.
Permissions, another way(修改方式2：以符号模式改变权限
