Features of a directory¶
A directory is a particular file: it is a two-column array. The first column contains the file names, the second contains their i-node number.
So to designate a file outside its directory, it is necessary to designate the directory in which it finds its name and then this name. Since a directory is a particular type of file, it is sufficient to designate a directory to designate the directory in which the name of the directory is located, then its name, and so on.
The origin of the designation string is a directory called the root of the file system. This is the only directory known directly by the system. Its i-node number is always 2.
The set of directories and files constitutes a tree for which the directories are branches and files the leaves.
We speak of the absolute name of a file when we designate the name of a file by its path from the root.
/home/toto/f1 means the file
f1 contained in the
toto directory itself contained in the home directory contained in the root directory (the root is designated by
Each directory contains two special entries by default:
.Designates the directory itself (or // current // directory)
..designates the // parent // directory
Thus, the command
cat has an absolute path
When using shell (shell), one can either designate a file by its absolute path, or by a relative path from the current directory. At all times, the user issues his commands from a current directory (the default directory is called home or home directory). Any file can be designated relative to its current directory.
For example, if you are located in the directory
/home/toto, the file
/usr/bin/cat can also be referred to as