tailieunhanh - Ubuntu The Complete Reference phần 5

Xây dựng các tập tin trình đơn KDE Được sử dụng bởi các ứng dụng KDE KDE biểu tượng máy tính để bàn sử dụng trong các ứng dụng và giúp ứng dụng KDE Mô tả hệ thống tự động bắt đầu với KDE dùng KDE máy tính để bàn | Chapter 12 Files Directories and Archives 271 both lunch and home george veglist using the Is command with the -l option. The first character in the line specifies the file type. Symbolic links have their own file type represented by an l. The file type for lunch is l indicating it is a symbolic link not an ordinary file. The number after the term group is the size of the file. Notice the sizes differ. The size of the lunch file is only 4 bytes. This is because lunch is only a symbolic link a file that holds the pathname of another file and a pathname takes up only a few bytes. It is not a direct hard link to the veglist file. ls -l lunch home george veglist -rw-rw-r-- 1 george group 793 Feb 14 10 30 veglist lrw-rw-r-- 1 chris group 4 Feb 14 10 30 lunch To erase a file you need to remove only its original name and any hard links to it . If any symbolic links are left over they will be unable to access the file. In this case a symbolic link will hold the pathname of a file that no longer exists. Hard Links You can give the same file several names by using the ln command on the same file many times. To set up a hard link you use the ln command with no -s option and two arguments the name of the original file and the new added filename. The ls operation lists both filenames but only one physical file will exist. ln original-filename added-filename In the next example the monday file is given the additional name storm. In this case storm is just another name for the monday file. ls today ln monday storm ls monday storm To erase a file that has hard links you need to remove all its hard links. The name of a file is actually considered a link to that file hence the command rm removes the link to the file. If you have several links to the file and remove only one of them the others stay in place and you can reference the file through them. The same is true even if you remove the original link the original name of the file. Any added links will work just as well. In the .