Day 2nd: File permissions and basic instructions for Linux systems

I. How to represent a file path

Under Windows, C:\Hjing\test.txt

Under Linux,/hjing/test.txt

Relative path representation method

Cat Test.txt, default is the file under the current directory, if not explained

Cat./test.txt explicitly specifies that the a.txt is in the current directory

Cat.. /hjing/test.txt explicitly specified, test.txt in the previous level directory Hjing sub-directory

Absolute path representation (always starting from the root directory)

/hjing/haha/test.txt

Filenames under windows are case-insensitive, such as: Test.txt = = TEST.txt

Linux file names are case-sensitive, such as: test.txt! = TEST.txt

Ii.. File permissions

For a directory,

If you do not have r permission, LS cannot view content

If you do not have W permissions, you cannot delete, add write operations

If you do not have X permissions, you cannot use the CD entry

RWX rwx rwx

Corresponds to 2 binary 111 111 111

Corresponds to decimal 7 7 7

Third, Linux common editing instructions

VI--is the command mode to enter, press A,i, you can insert the operation, exit first press ESC, and then perform the following actions

: W-Save

: Q, exit

: Wq-Save exit

: q! --Not save exit

CD/, enter the root directory

Terminal VI mode displays line number operations:

1. Return to the home directory, CD enter

2. Generate a. vimrc file, Vi. VIMRC

3. Enter I in the Open command, enter edit mode input set Nu

4. Save exit

The Shell:linux character interface has many different shells, which are the human-computer interaction modes of the character interface.

SH is a very old and basic Unix shell.

If you do not specify a shell when creating a user, the default shell is sh when you log in to this user.

The shell is also a program, typically in the/bin directory

GCC is the Linux system itself, the Linux operating system itself is compiled with GCC

CC is automatic on UNIX systems.

Windows does not bring its own GCC directives.

Install the GCC method under Windows:

1. Download the installation version directly to the GCC website

2. When QT is installed, Qt comes back with a GCC version, found in the QT installation directory Gcc.exe in Windows

Under the installation path, and then put this path into the Windows System environment variable path, in patch last Mina

: Installation path for GCC

Not tested.

In the Linux setup system you can find out how to execute the program in the current directory

1. Go back to the user's home directory, CD enter

2. In the user's home directory, open the file. Profile (Ubuntu),. Bash_profile (Redhat)

3. At the end of the. profile file, add a row of export path= $PATH:. Note that this is case sensitive.

4, Save exit

5,source. Profile (Redhat) source. bahs_profile

All of the above changes are specific to a particular user, such as User a modified, but User B will not take effect, such as root changes, then other users will not take effect

SFTP inside to set the remote path and local path

CD 1 Enter the 1 directory of Linux that is connected remotely

LCD \test

Get abc.c Get file abc.c from remote directory, put in local directory test

How to use http.tar.gz source code files

Step one, upload the file to Linux

Step two, unzip

Gzip-d http.tar.gz

TAR-XVF Http.tar

Step three, go to the HTTP directory

CD HTTP

Fourth step, compile this source code

Make

Fifth step, switch to root user

Su

Sixth step, start the program

./myhttp Start

Listen success

Myhttp begin

The delegate program started successfully.

Day 2nd: File permissions and basic instructions for Linux systems