One, relative path and absolute path:
A, Absolute path: The path that is written by the root directory/start, for example/usr/share/doc
B, relative path: a path that is not written by the root directory/start.
Second, the relevant operation of the directory:
1. CD: Directory switch
CD ~vbird;
CD ~;<== switch to the current user's working directory
CD.; <== return to the previous level directory
Cd-;(back to previous directory)
Cd/usr/share;
CD share;
2. PWD: Displays the current directory
Pwd-p; <== shows the actual directory, not just the directory name of the connection file itself.
3, mkdir: Create directory, need to have permission
mkdir test; <== creates a new directory under the current working directory.
Mkdir-p Test/test1/test2; <== Create a directory recursively (not recommended);
Mkdir-m 711 Test2; <== directly set permissions on the file.
4, RmDir: Delete empty directory, note is empty directory.
RmDir test;
Rmdir-p Test1/test2/test3; <== is still not recommended for use. It is recommended to use the RM command.
Iii. variables for executing file paths: $PATH
1, Echo $PATH: Between the different paths to: Connect
2. New example: Path= "$PATH":/root